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Cumulative Library of Essay Questions and Answer Guides for the Abdomen, Pelvis, and Perineum

Uterus and Adnexa - September 13, 2012

A hysterosalpingogram determines patency of the uterine ostia and uterine tubes. Radiographic contrast is injected into the uterine cavity through the vagina and cervix. If the fallopian tubes are patent, dye fills spills into the abdominal cavity. Blockages are then ruled out as the cause of a patient's infertility. Indicate your understanding of the uterus, uterine tubes, and ovary as to structure, orientation, relationships (anterior, posterior, superior, inferior, medial, lateral), ligamentous support, peritoneal associations, innervation (preganglionic, postganglionic, and visceral afferent pathways), vasculature, and lymphatics. (12 pts)

Uterus

  • Structure
    • Pear shaped hollow organ - 8cm long, 5cm wide
    • myometrium and endometrium
    • cervix, body, fundus
    • external os, cerivical canal, internal os, uterine cavity
  • Orientation
    • anteflexed and anteverted (lengthens posterior fornix vagina)
  • Support
    • intraperitoneal organ
    • Broad lig. - visceral lig (peritoneum)
      • lateral uterus to parietal peritoneum of lateral pelvic wall
    • fibrous ligs derived from endopelvic fascia
      • utereosacral, pubouteral, and lateral cervical (Cardinal) ligs.
    • round lig to lateral anterior pelvic brim - anterior lamina broad lig.
    • ovarian lig to posterior abdominal wall via suspensory lig. ovary
  • Relationships
    • anterior: bladder, vesicouterine pouch
    • posterior: rectum, rectouterine pouch
    • superior: false pelvis, abdominal cavity
    • inferior: vagina, posterior fornix, rectouterine pouch
    • lateral: broad lig, pelvic wall, ovary, uterine tube
  • vasculature and lymphatics,
    • uterine a. at the cervix and ovarian a. at the fundus
      • ovarian v. to ivc on right and left renal v. on left
      • uterine venous complex into internal iliac vv.
    • fundus drains lymph to upper lumbar nodes along ovarian vessels
    • superior body near round ligament drains lymph to superficial inguinal nodes
    • cervix drains lymph toward internal iliac nodes
  • innervation
    • sympathetic by way of inferior hypogastric plexus to uterovaginal plexus along uterine a.
      • preganglionic in IMLCC lower thoracic and upper lumbar
      • postganglionic in microscopic ganglia of aortic and hypogastric plexuses
    • parasympathetic: pelvic splanchnic if present
    • sensory pain follow sympathetic pathways (eg. hypogastric nerves)

Uterine Tube

  • Structure
    • shaped as a salpinx and about 10 cm long
    • connects uterine cavity to the peritoneal cavity
    • isthmus, ampulla, infundibulum, fimbriae
  • Orientation
    • courses laterally from fundus of uterus toward pelvic wall
    • intraperitoneal in superior free edge of broad lig.
    • cradles ovary as a posterior relation
  • Support
    • mesosalpinx - visceral lig (peritoneum) part of broad lig.
      • continuous with mesovarium
    • ovarian lig to posterior abdominal wall via suspensory lig. ovary
  • Relations
    • anterior: bladder, vesicouterine pouch
    • posterior: broad lig., rectum, rectouterine pouch, ovary
    • superior: false pelvis, abdominal cavity
    • inferior: broad lig., rectouterine pouch
    • lateral: broad lig, pelvic wall, ovary, ovarian fossa, uterine tube
    • medial: fundus and body of uterus
  • vasculature and lymphatics,
    • tubal a., uterine a. at the cervix and ovarian a. at the fundus
    • uterine venous complex to internal iliac vv
    • drains lymph to upper lumbar nodes along ovarian vessels
    • drains lymph to superficial inguinal nodes
    • drains lymph toward internal iliac nodes
  • innervation
    • sympathetic by way of inferior hypogastric plexus to uterovaginal plexus along uterine a.
      • preganglionic in IMLCC lower thoracic and upper lumbar
      • postganglionic in microscopic ganglia of aortic and hypogastric plexuses
    • sympathetic by way of ovarian plexus
    • parasympathetic: unknown if present
    • sensory pain follow sympathetic pathways

Ovary

  • structure and support
    • The ovary is roughly cylindrical about 3 cm long and 1 cm in diameter. The visceral peritoneum covering the ovary gives way to a specialized germinal epithelial cell layer. The egg is able to penetrate this layer and enter the peritoneal cavity.
    • The ovary is suspended from the posterior lamina of the broad ligament by the mesovarium -- a peritoneal ligament. Supporting the superior pole of the ovary to the pelvic brim is the suspensory ligament of the ovary. Supporting the inferior pole of the ovary to the lateral uterus is the ovarian ligament.
    • relationships
      • superior to the ovary is the pelvic brim and suspensory ligament
      • inferior to the ovary is the uterine wall and the ovarian ligament
      • anterior to the ovary is the broad ligament, uterine tube, and fimbria of uterine tube
      • posterior to the ovary is the rectum and pelvic floor
      • medial to the ovary is the pararectal fossa, rectouterine pouch, fundus of the uterus
      • lateral to the ovary is the ovarian fossa (internal iliac a. and ureter), psoas major muscle, and obturator n.
    • innervation (motor and sensory)
      • Parasympathetic preganglionic cell bodies are located in the central gray of the spinal cord (IMLCC) at levels S2-4. Preganglionic fibers enter the inferior hypogastric plexus by way of the pelvic splanchnic nerves. The inferior hypogastric plexus contributes a uterine plexus and then to the ovarian plexus. Postganglionic parasympathetic cell bodies are located in intrinsic ganglia of the ovary. The above pathway assumes that the uterovaginal plexus reaches the ovary. This is not known for certain. Parasympathetic pregangionic contributions from the vagus n. may also follow the ovarian plexus.
      • Sympathetic preganglionic cell bodies are located in the interomedial lateral cell column at cord levels T10 (and perhaps T11-12). Preganglionic fibers follow the lesser and least splanchnic nerves to aortic ganglia near (and including) the superior mesenteric ganglion and the aorticorenal ganglion. Postganglionic fibers from these ganglia enter the aortic plexus and extend along the ovarian artery as the ovarian plexus. Visceral afferent pathways follow the sympathetic pathways up to the T10 spinal level. Additional visceral pathways follow parasympathetic pathways back to the S3-4 spinal levels.
    • blood supply and lymphatics
      • The arterial supply is mostly from the ovarian arteries. These are paired arteries arising from the anterolateral surface of the aorta near the level of the third lumbar vertebra. The ovarian veins arise from the IVC on the right and the left renal vein on the left. Additional blood supply is by ascending branches of the uterine vessels (ovarian br.) that anastomose with the ovarian vascular supply. Lymph drainage is primarily along the embryological decent of the ovary. This includes upper lumbar nodes in the vicinity of the renal arteries. Much of the vascular supply reaches the ovary through the suspensory ligament.

  • Prolaps of Uterus
    • Weakening of the ligamentus support of the uterus leads to prolapse
      • most noteably, the lateral cervical ligs and important

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Spermatic Cord and Indirect Hernia - September 13, 2012

Indirect inguinal hernias result from a patent processus vaginalis. Abdominal viscera may move through the processus vaginalis into the scrotum. Review the anatomy of the spermatic cord. Include contents, coverings, fascial boundaries, innervation, vasculature, lymphatics, and relationships. Discuss the pathway and location of an indirect inguinal hernia that has descended into the scrotum. (12 pts)

General Comments

  • The spermatic cord is the pedicle of testis. Beginning at the deep ring, the spermatic cord transmits the contents of the deep ring from the abdominopelvic cavity to the scrotum.
  • The pathway from the deep ring to the scrotum marks the "descent" of the testis.
  • A peritonealized surface of the testis causes a trailing diverticulum know as the processes vaginalis.
  • Applied to the anterior aspect of the testis is the visceral layer of tunica vaginalis.
  • The deep ring marks the beginning of the inguinal canal and is located: at the midinguinal point; lateral to the inferior epigastric artery; and slightly more than 1 cm superior to the inguinal ligament.
  • At the deep ring the spermatic cord receives the internal spermatic fascia derived from transversalis fascia. Within the inguinal canal the internal oblique contributes the cremasteric fascia.
  • The cord exits the inguinal canal by way of the superficial ring.
  • The superficial ring, a defect in the external oblique aponeurosis, contributes the external spermatic fascia.
  • The testis, at the distal extent of the cord, ultimately resides within the scrotum. It is tethered to the most inferior aspect of the scrotum by the scrotal ligament.
  • The external spermatic fascia (deep fascia) is opposed to dartos fascia (superficial fascia).

Internal Spermatic Fascia. Structures that pass through the deep ring were retroperitoneal and reside within the internal spermatic fascia derived from transversalis fascia.

  • processes vaginalis - a trailing diverticulum of peritoneum that accompanies the testis during the "descent."
  • Distally, within the scrotum, the processes vaginalis opens into the tunica vaginalis
  • Extraperitonial connective tissue
  • Testicular artery - paired branches from lumbar aorta near renal arteries
  • Testicular vein - proximally the testicular vein consists of 3-4 veins
  • Distally the testicular surrounds the testicular artery forming the pampinifrom plexus veins numbering 10 to 12 veins
  • Left testicular vein drains into left renal vein and the right testicular vein drains into the IVC near the renal artery
  • Testicular lymphatics - provide drainage to upper lumbar nodes, to lumbar lymph ducts, to cysterna chyli
  • Testicular autonomic plexus - sympathetic preganglionic cell bodies in IMLCC T10(11-12)
    • Symmpathetic postganglionic cell bodies in superior mesenteric ganglion
    • Parasympathetic preganglionic fibers derived from the vagus nerve
  • Afferent "pain" fibers following sympathetic pathways to spinal levels T10(11-12)
  • Vas deferens - under sympathetic control, the walls (2-3 mm thick) of the vas deferens contract to discharge spermatozoa
  • Within the cord the Vas deferens lies posterior to the testicular artery
  • Distally, the Vas deferens forms the tail of the epididymis at the posterior inferior pole of testis
  • Further distally the tail gives way to the body and then to the head of the epididymis at the posterior superior pole
  • Deferential artery - branch of the internal iliac artery vascularizes the vas deferens and anastomoses with the testicular artery
  • Deferential autonomic plexus - derived from the superior/inferior hypogastric autonomic plexus to prostatic plexus
    • Parasympathetic preganglionic fibers possibly derived from pelvic splanchnics (S2-4)
    • Afferent "pain" fibers following sympathetic pathways to spinal levels T10(11-12)
  • Deferential lymphatics - drainage to internal iliac nodes, to lumbar lymph ducts, to cysterna chyli
  • Genital branch of genitofemoral nerve - mediates efferent component of cremasteric reflex
  • Cremesteric artery - branch of inferior epigastric artery vascularizes the tunics

The cremesteric fascia is superficial to the internal spermatic fascia and deep to the external spermatic fascia

  • Derived from internal oblique muscle, the cremesteric fascia contributes to the cord within the inguinal canal
  • Genital branch of the genitofemoral nerve - provides somatic motor supply
  • Cremesteric artery - branches provide vascularization to the cremesteric fascia

The external spermatic fascia is superficial to the cremesteric fascia and is the outer most tunic

  • Derived from the external oblique, the external spermatic fascia extends to the cord beyond the superficial ring
  • Within the scrotum the external spermatic fascia is deep to dartos tunic

Path of indirect inguinal hernia

  • An indirect hernia follows the embryologic "descent" of the testis indirectly out the superficial ring by way of the deep ring.
  • A patent processes vaginalis allows herniated material to pass through the deep ring lateral to the inferior epigastric artery
  • Herniated material passes through the inguinal canal and out the superficial ring - superior and medial to pubic tubercle
  • Distally, the hernia is arrested by the tunica vaginalis
  • In the case of herniated intestine, visceral peritoneum is directly opposed to visceral and parietal tunica vaginalis
  • Palpation of the hernia occurs at the anterior aspect of the testis within the scrotum
  • The long and curvaceous path of an indirect hernia make strangulation a distinct possibility

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Lesser Sac - September 13, 2012

Peptic ulcer disease may erode the posterior wall of the stomach and spill stomach contents into the lesser sac. Define the boundaries (including spaces and/or recesses) of the lesser sac. Account for dull pain followed by sharp pain when the posterior stomach wall perforates. Discuss the pathway of spilled stomach contents that pass from the lesser sac into the greater sac, and the location of these contents with respect to body position. (12 pts)

General comments

  • The lesser sac is a diverticulum in the superior region of the peritoneal cavity. Communication with the greater sac is via the epiploic foramen. For the most part, the lesser sac is posterior to the stomach and liver, anterior to the pancreas and diaphragm, superior to the duodenum, pancreas, and transverse mesocolon, inferior to the liver and diaphragm, left of the caudate, and right to the gastroleino and leinorenal ligs.

Superior recess - posterior to liver, begins at epiploic foramen

  • anterior - caudate lobe of liver and lesser omentum
  • posterior - diaphragm
  • superior - diaphragm
  • inferior - lesser recess
  • right - liver, ligamentum venosum
  • left - splenic recess

Inferior recess - inferior ot the right gastropancreatic fold (common hepatic a.)

  • anterior - hepatoduodenal ligament, duodenum, gastrocolic ligament
  • posterior - pancreas, tail of pancreas enters leinorenal ligament
  • superior - superior recess
  • inferior - transverse mesocolon
  • right - liver
  • left - gastroleino ligament

Splenic recess - left of gastroepiploic fold (left gastric a.)

  • anterior - stomach, gastrocolic ligament (greater omentum)
  • posterior - aorta, left suprarenal gland, upper pole left kidney, splenic a., diaphragm
  • superior - liver and diaphragm
  • inferior - inferior recess
  • right - caudate lobe, superior recess
  • left - gastroleino and leinorenal ligaments

Epiploic foramen - communication between lesser and greater sacs

  • anterior - hepatoduodenal ligament
  • posterior - inferior vena cava
  • superior - caudate lobe liver
  • inferior - duodenum
  • right - opening into hepatorenal recess and right paracolic gutter
  • left - lower recess of lesser sac

Pathway of Materials?

  • Person rolls to the right - contents of lesser sac enter the greater sac via the epiploic foramen
  • Person returns to supine - contents enter the hepatorenal recess
  • Person stands - contents follow the right paracolic gutter to the pelvic basin and the rectouterine or rectvesical pouch
  • General discussion of abdominopelvic gutters

Somatic afferent innervation

  • parietal peritoneum of the posterior wall innervated by thoracoabdominal nerves

Why sharp pain?

  • Irritation of the parietal peritoneum of the posterior wall activates somatic afferent activity in the thoracoabdominal nerves (intercostals, subscostals, iliohypogastric, ilioinguinal) and possibly phrenic nerve.

Vascular supply of the Walls - vascular supply is by regional aa and vv (optional)

  • posterior - splenic av
  • anterior - common hepatic, right gastric, left gastric, aa
  • inferior - right and left gastroepiploic aa vv, supra- and retroduodenal aa vv
  • superior - inferior phrenic av
  • left - short gastric aa vv
  • right - right and left gastric aa vv

Lymphatic drainage of the Walls - follows vascular supply (optional)

  • paraaortic nodes to lumbar trunks to cysterna chyli
  • diaphragmatic border involves mediastinal and axillary nodes (anterior wall vasculature)

Autonomic Innervation to the Walls (optional)

  • sympathetic preganglonics - mostly from greater and lesser splanchnic nerves (cell bodies in imlcc of T5-11)
  • sympathetic postganglionics - mostly from celiac plexus (cell bodies in celiac ganglion)
  • parasympathetic preganglionics - from vagus nerve (cell bodies in dorsal motor nucleus of vagus nerve)
  • parasympathetic postganglionics - intrinsic ganglia

Visceral afferent innervation from the Walls (optional)

  • "pain" follows sympathetic pathways to spinal levels T5-11

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Ischiorectal Fossa - September 15, 2011

Discuss the boundaries and contents of the ischiorectal fossa, fascial specializations, vascularization, innervation, lymphatic drainage, the relationship of the ischiorectal fossa to the superficial and deep pouches, and provide an explanation of your observation that urine does not accumulate in the superficial pouch. (12 pts)

General

  • Wedge shaped area located between the ischial tuberosites and the anorectal canal and consisting of a posterior recess and an anterior superior recess.

Boundaries of Anterior Superior Recess

  • Superior - inferior fascia of the pelvic diaphragm, most lateral and superior is arcus tendineous
  • Inferior - superior fascia of the urogenital diaphragm
  • Anterior - fusion of superior fascia urogenital diaphragm (transverse perineal ligament) with inferior fascia of pelvic diaphragm at the pubic bone
  • Posterior - open into the posterior recess of the ischiorectal fossa
  • Lateral - inferior - conjoint ramus, intermediate - oburtator internus muscle
  • Medial - fusion of the inferior fascia of the pelvic diaphragm with superior fascia urogenital diaphragm at urogenital hiatus

Boundaries of Posterior Recess

  • Superior - inferior fascia of the pelvic diaphragm
  • Inferior - medial: perianal skin, lateral: gluteus maximus
  • Anterior - superior to posterior free edge urogenital diaphragm: anterior superior recess of the ischiorectal fossa, inferior to posterior free edge of urogenital diaphragm: superficial perineal fascia (Dartos)
  • Posterior - gluteus maximus
  • Lateral - gluteus maximus
  • Medial - anal canal

Fascial specializations

  • Arcus tendineus - thickening of obturator internus fascia, faces pelvic cavity on superior aspect and ischiorectal fossa on inferior aspect
  • Pudendal canal - thickened covering of obturator internus fascia over falciform edge along medial ischial tuberosity forms osseofibrous pudendal canal from lesser sciatic foramen to the posterior free edge of the urogenital diaphragm at the conjoint ramus

Contents and relationships

  • Loose areolar fat - accomodate distention
  • Anal canal
  • Pudendal nerve and branches - inferior rectal, perineal, posterior scrotal, dorsal nerve
  • Internal pudendal artery and branches - inferior rectal, perineal, posterior scrotal, dorsal artery, deep artery, artery to the bulb

Fascial Barriers to the Superficial Pouch

  • Infection does not spread from the ischiorectal fossa into the superficial pouch because Scarpa's fascia attaches to the posterior free edge of the UG diaphragm. This attachment provides part of the anterior border of the ischiorectal fossa at levels inferior to the posterior free edge of the urogenital diaphragm.

Fascial Barriers to the Deep Pouch

  • Infection does not spread from the ischiorectal fossa into the deep pouch because the superior fascia of the urogenital diaphragm provides a fascial barrier between the anterior superior recess of the ischiorectal fossa and the deep pouch.

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Pancreas - September 15, 2011

Review the anatomy of the Pancreas. Include structure, supports, relationships, vascularization, innervation, and lymphatic drainage. (12 pts)

General

The pancreas is a tear-drop shaped finely lobulated glandular structure associated with the duodenum. Named parts include the head, uncinate process, neck, body, and tail. It lies transversely to the anterior surface of the aorta with the neck and uncinate process on the anterior surface of the aorta and IVC. The tail extends laterally to left as far as the leinorenal ligament. The longitudinal extent is about 6 - 8 inches. The width at the head is 2 - 3 inches. The chief and accessory pancreatic ducts discharge digestive enzymes into the duodenum at the major and minor duodenal papilla. The chief pancreatic duct runs the transverse length of the pancreatic tissues and drains toward the ampulla of Vater. In turn, discharge from the ampulla is regulated by the sphincter of Oddi. The accessory pancreatic duct drains the superior aspect of the head.

Structure

  • The pancreas is located retroperitoneal and forms much of the floor of the lesser sac
  • The head extends from the right side of the L1-3 lumbar vertebrae
  • The head is cradled by all parts of the duodenum in the comfortable embrace of a "C"
  • The head, neck crosses the IVC, the anterior vertebral bodies of L1-3 and the aorta
  • The body crosses the duodenojejunal junction
  • The neck, body, and tail extend to the left as far the the hilum of the spleen
  • The uncinate process creates the pancreatic incisure at the inferior border of the head
  • The pancreatic incisure "takes a bite" out of the superior mesenteric vein and artery (vein to right of artery)
  • The uncinate process lies posterior to the superior mesenteric vein and artery

Relationships

  • Transverse mesocolon crosses lower aspect of head and inferior margin of neck and body
  • Anterior surface faces lessor sac and stomach - incision of gastrocolic ligament provides surgical access
  • Anterior surface of head touches all four parts of duodenum
  • Posterior to the head is the hilum of the right kidney along with the right renal vessels
  • Posterior to the head is the common bile duct on the right and the portal vein to the left
  • Posterior to the neck is the IVC and the aorta
  • Posterior to the body is the left kidney, suprarenal gland, and right crus of the diaphragm
  • The celiac trunk is immediately superior to the upper margin of the head and neck
  • The splenic artery runs retroperitoneal along the superior margin of the neck, body, and crosses anterior to tail
  • The common hepatic artery crosses the anterior surface of the upper margin of the head to the right side
  • The splenic vein runs directly posterior to the neck and body
  • The inferior mesenteric vein crosses the posterior surface of the lower margin of the neck

Vasculature

  • Head - arterial arcades from the celiac (foregut) and supermesenteric arteries (midgut)
    • the superior anterior and posterior pancreaticoduodenal arteries from the gastroduodenal artery
    • the inferior anterior and posterior pancreaticoduodenal arteries from the superior mesenteric artery
  • Neck - dorsal pancreatic artery from aorta
  • Body - great pancreatic artery from splenic artery
  • Tail - caudal pancreatic arteries from splenic artery
    • The inferior pancreatic artery, an anastomotic network within the pancreas, provides all tissues
    • Venous drainage follows arterial channels to eventually drain into the SMV, splenic vein, and portal vein

Lymphatic drainage of the pancreas

  • Lymphatics tend to follow blood vessels
  • Superior margin of head into celiac nodes
  • Inferior margin of head into superior mesenteric nodes
  • Anterior surfaces into pyloric nodes
  • Body and tail into pacreaticolienal nodes along spenic vessels in turn into celiac nodes or upper lumbar nodes
  • Paraaortic nodes drain into lumbar lymph ducts and then into cysterna chyli

Innervation of the pancreas

  • Celiac plexus innervates superior head and neck as well as the body and tail
  • Superior mesenteric plexus innervates the inferior head
  • Sympathetic preganglionic cell bodies - IMLCC of T5-9 to fibers in greater splanchnic nerve
  • Sympathetic postganglionic cell bodies - celiac ganglion to fibers in celiac plexus
  • Sympathetic preganglionic cell bodies - IMLCC of T10-11 to fibers in lesser splanchnic nerve
  • Sympathetic postganglionic cell bodies - superior mesenteric ganglion to fibers of superior mesenteric plexus
  • Parasympathetic preganglionic cell bodies - dorsal motor nucleus vagus nerve to fibers of celiac and superior mesenteric plexuses
  • Visceral afferent pain - follow thoracic splanchnic nerves to spinal levels T5-11

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Anterior Abdominal Wall - September 15, 2011

Review the anatomy of the anterior abdominal wall. Include structure, supports, relationships, vascularization, innervation, and lymphatic drainage. (12 pts)

General

  • Between the costal margins and the bony pelvis
  • Muscular - relaxes on distension and contracts on compression
  • Compression raises intra-abdominal pressure to stabilize vertebral column - increasing muscle tone is a treatment for back pain
  • Compression protects abdominopelvic viscera from injury
  • Forced expiration of the lungs and evacuation of pelvic viscera
  • Neurovascular plane - between internal oblique and transversus abdominis

Muscles

  • External oblique - origin: iliac crest for trunk flexion (ribs for compression), insertion: lower 7 ribs (iliac crest for compression), inferior free edge is inguinal ligament, anterior half is aponeurosis contributing to rectus sheath and linea alba and attaching to pubic crest
  • Internal oblique - orgin: lateral two-thirds inguinal (different accounts), iliac crest, and thoracolumbar fascia, insertion: lower 3 ribs, anterior half is aponeurosis contributing to rectus sheath and conjoined tendon
  • Transversus abdominis - origin: inquinal ligament lateral to internal oblique, inner lip iliac crest, thoracolumbar fascia, lower six costal cartilages, inserts upon itself by way of the rectus sheath and linea alba
  • Rectus abdominis - origin: pubic crest, insertion: 5, 6, and 7 costal cartilages, tendinous intersections divide muscle into sections, pyramidalis

Ligaments

  • Linea alba - midline raphe: intertwining of aponeurotic fibers from external oblique, internal oblique, and transversus abdominis
  • Inguinal ligament - inferior aspect of the external oblique aponeurosis
  • Lacunar ligament - external oblique, medial boundary of femoral ring
  • Pectineal ligament - external oblique, posterior boundary of femoral ring
  • Conjoint tendon - fusion of internal oblique and transverses abdominis to pectin pubis, guards against direct inguinal hernia
  • Median umbilical ligament - obliterated urachus
  • Lateral umbilical ligaments - obliterated umbilical arteries
  • Fundiform ligament - derived from Scapa's fascia and supporting the dorsum of the penis/clitoris to the inferior aspect of linea alba
  • Medial and lateral crua - contribute to anterior wall of inguinal canal and to the margin of the superficial ring, external oblique, external oblique
  • Intercrural fibers - contribute to anterior wall of inguinal canal and aproximate the medial and lateral crura, external oblique
  • Reflected inguinal ligament - posterior/inferior wall of superficial ring, external oblique

Fascia and Fascial Specializations

  • The rectus sheath surrounds the rectus abdominis muscle. Boudaries - superior: costal cartilages, inferior: pubic crest, anterior: anterior lamina rectus sheath, posterior: posterior lamina rectus sheath, medial: linea alba, lateral: linea semilunaris. Contained with the rectus sheath are the rectus abdominis, superior and inferior epigastric vessels, anterior branches of intercostal, subcostal, and iliohypogastric nerves, tendinous intersections.
  • Superficial to deep lateral to rectus sheath: epidermis - dermis - campers fascia (fatty) - Scarpa's fascia (membranous) - deep fascia - external oblique - internal oblique - transversus abdominis - transversalis fascia - extraperitoneal connective tissue - parietal peritoneum
  • Superficial to deep at rectus sheath superior to arcuate line: epidermis - dermis - campers fascia (fatty) - Scarpa's fascia (membranous) - deep fascia - external oblique aponeurosis - internal oblique aponeurosis anterior layer - rectus abdominis - internal oblique aponeurosis posterior layer - transversus abdominis aponeurosis - transversalis fascia - extraperitoneal connective tissue - parietal peritoneum
  • Superficial to deep at rectus sheath inferior to arcuate line: epidermis - dermis - campers fascia (fatty) - Scarpa's fascia (membranous) - deep fascia - external oblique aponeurosis - internal oblique aponeurosis anterior and posterior layers fused - transversus abdominis aponeurosis - rectus abdominis - transversalis fascia - extraperitoneal connective tissue - parietal peritoneum
  • The superifical fascia, starting superior at the level of the umbilicus and extending inferior, is made up of two layers - a fatty layer (Camper's) and a membranous layer (Scarpa's). Scarpas fascia is attached to deep fascia along the linea alba and extends inferiorly onto the penis (Colle's), scrotum (Dartos), or labia majora (superficial perineal fascia). Scarpa's fascia contributes the fundiform ligament from the anterior abdmominal wall to the dorsum of the penis/clitoris. Most inferiorly, Scarpa's fascia or its derivatives attach to the posterior free edge of the urogenital diaphragm and to the fascia lata about one inch inferior to the inguinal ligament.
  • The rectus sheath does not have a aponeurotic posterior lamina at levels inferior to the arcuate line and superior to the insertions of the internal oblique. Thus, the posterior lamina is non-muscular inferior to the approximate mid-point between umbilicus and pubic crest and is, again, non-muscular superior to the xiphoid process.

Nerves and innervation

  • Motor - lower intercostal nerves (T6-11), subcostal, iliohypogastric - travel in neurovascular plane and pierce linea semilunaris
  • Sensory - lower intercostal nerves (T6-11), subcostal, iliohypogastric - travel in neurovascular plane and pierce linea semilunaris, anterior intercostal nerves, T8 at xiphysternal region, T10 at umbilicus, and T12 at suprapubic region, subcostal at pubic ridge

Vasculature Supply

  • Supeficial veins - portal system: paraumbilical veins, caval system: lateral thoracic, thoracoepigastric, superficial epigastric, superficial circumflex iliac vein
  • Superficial arteries - superficial circumflex iliac, superficial epigastric, superficial pudendal
  • Caput Medusa - paraumbilical veins (portal system) reverse flow, dilate, and shunt to caval system at inferior vena cava (great saphenous - femoral - external iliac - IVC)and superior vena cava (axillary - subclavian - brachiocephalic - SVC)
  • Vessels in the neurovascular plane (deep the internal oblique and superficial to transversus abdominis) - intercostal arteries and veins from lower thoracic levels and lumbar arteries, musculophrenic, deep circumflex iliac artery, iliolumbar artery
  • Vessels within the rectus sheath - superior and inferior epigastric arteries and veins
  • Anterior aortic shunt - subclavian - internal thoracic - superior epigastric - inferior epigastric - external iliac

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Prostate - September 16, 2010

Review the anatomy of the prostate. Include structure, supports, relationships, vascularization, innervation, and lymphatic drainage. (12 pts)

Structure of the prostate

  • The prostate, a walnut sized structure located superior to the pelvic floor and inferior to the neck of the bladder, is uniquely in the male. The glandular structure is encapsulated in a shiny capsule that is, in turn, surrounded by a thickened periprostatic fascia derived from pelvic visceral fascia. The posterior aspect of this fascia is especially thickened and is named the fascia of Denonvillier. A considerable amount of smooth muscle within the stroma adds firmness to the gland. Glandular follicles drain by way of 15 - 20 prostatic ducts into the prostatic sinuses of the prostatic urethra.
  • The median lobe of the prostate is posterior to the prostatic urethra. This lobe includes the ejaculatory ducts, seminal colliculus, urethral crest, and most distal aspect of the uvula. Benign prostatic hypertrophy commonly affects the median lobe. In addition to the median lobe, there designated two lateral lobes and an anterior lobe. There are no anatomical landmarks delineating the lobes.
  • The prostatic urethra occupies about 2.5 cm of the central prostate. The superior posterior wall receives a projection of the uvula that becomes the urethral crest within the prostatic urethra. Approximately one-third of the way into the prostatic urethra the urethral crest widens for 2-4 mm to form the seminal colliculus. The ejaculatory ducts empty into the prostatic urethra on either side of the seminal colliculus. Lateral to the seminal colliculus the posterior wall deepens posteriorly to the form the prostatic sinuses receiving the prostatic ducts. The utrical, thought to be a vestigial uterus in the male, might be visible on the anterior surface of the seminal colliculus.

Support of the prostate

  • Puboprostatic ligament - Condensation of pelvic visceral fascia secures prostate to anterior pelvic wall
  • Lateral ligaments - Condensation of pelvic visceral fascia secures prostate to lateral pelvic wall
  • Median umbilical ligament - obliterated urachus secures bladder, and thus prostate, to anterior abdmoninal wall
  • Levator prostatae muscle - fibers of pubococcygeus insert into the prostatic fascia and capsule

Relations of the prostate

  • Inferior - superior fascia fascia of the pelvic diaphragm located at the urogental hiatus of the urogenital diaphragm
  • Superior - neck of the bladder and the uvula
  • Anterior - inferior aspect of the pubic symphysis
  • Posterior - rectum, rectovesical space
  • Posterior/superior - ampulla of ductus deferens, ureter, seminal vesical
  • Lateral - pelvic diaphragm, superior aspect of conjoint rami, pelvic wall

Vasculature of prostate

  • The arterial supply to the prostate is derived from the inferior vesical, middle rectal, and inferior rectal (internal pudendal) arteries. Each of these arteries is a branch of the internal iliac artery
  • The prostatic venous plexus is superficial to the capsule and deep to prostatic fascia. It receives the deep dorsal vein of the penis and the vesical venus plexus. Venus drainage to internal iliac veins follow the aforementioned arterial pathways. There is free drainage by the lateral sacral veins into the internal vertebral venus plexus. This drainage is thought to account for the propensity of prostatic cancers to metastasize to the vertebral column.

Innervation of prostate

  • The prostatic autonomic plexus is derived from the inferior hypogastric plexus. Preganglionic sympathetic cell bodies are located in the IMLCC of L1-2. Preganglionic fiber pathways involve the superior hypogastric plexus and the right and left hypogastric nerves. Further, preganglionic fibers can follow the common iliac plexus to the internal iliac plexus and arrive at the prostatic plexus by way of the arterial supply. Postganglionic sympathetic cell bodies are thought to be located in unnamed ganglia distributed throughout the inferior hypogastric plexus. Additionally, preganglionic fibers within the sacral sympathetic trunk contribute sacral splanchnics to the inferior hypogastric plexus.
  • Parasympathetic preganglionic cell bodies are located in the IMLCC of S2-4. Pelvic splanchnic nerves convey preganglionic fibers to the inferior hypogastric plexus. Postganglionic cell bodies are located in enteric ganglia at the target location.
  • The inferior hypogastric plexus form extensions that spread out over the pelvic organs. The prostatic autonmomic plexus froms a collection of nerves the run along the lateral aspect of the prostate and onto the the membranous urethra to enter the cavernous tissue of the perineum. The cavernous nerves provide the parasympathetic innervation to the helecine arteries. To avoid impotency, it is essential that the cavernous nerves are preserved during prostatic surgery.

Lymphatic drainage of prostate

  • The internal tissues of the prostate have relatively litte lymphatic drainage. For this reason, it is thought that metastatic desease reaches the vertral column through venous channels (see above).
  • The prostatic capsule and fascia drain into internal iliac nodes to common iliac, to lumbar, to cysterna chyli.

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Scarpa's Fascia - September 16, 2010

Discuss the boundaries of Scarpa's fascia and its derivatives with respect to the containment of urine in the male. Specify the fascial layers associated with the accumulation of urine. Discuss whether urine will be found in the ischiorectal fossa. (12 pts)

General comments

  • Scarpa's fascia is membranous tela subcutanea. This fascia is capable of holding sutures and defines a potential space between it and deep fascia. This space can be invaded by infection or the extravasation of urine. The tear in the inferior fascia of the urogenital diaphragm transmits urine from the deep pouch to the superficial perineal pouch. The intact superior fascia of the urogenital diaphragm together with the intact superficial perineal fascia will prevent urine from entering the ischiorectal fossa. The accumulation of urine is restricted by the boundaries of Scarpa's (membranous) fascia.

Anterior abdominal wall - between Scarpa's fascia and deep fascia of external oblique

  • Superior: Scarpa's fascia attaches to deep fascia in finger like projections at level of umbilicus
  • Inferior medial: open passage to scrotum
  • Inferior lateral: passage to thigh
  • Lateral: near mid-axillary line at the thoracolumbar fascia
  • Medial: along the linea alba, fundiform ligament
  • Anterior: Scarpa's fascia
  • Posterior: deep fascia of external oblique

Thigh - between Scarpa's fascia and fascia lata

  • Inferior: 2 cm below inguinal ligament
  • Superior: open
  • Lateral: iliotibial tract
  • Ledial: pubic ramus
  • Anterior: Scarpa's fascia
  • Posterior: fascia lata

Scrotum - between Darto's tunic (Scarpa's derivative) and external spermatic fascia (deep fascia)

  • Superficial: Darto's tunic
  • Deep: external spermatic fascia

Penis - between Colle's fascia (Scarpa's derivative) and Bucks fascia (deep fascia)

  • Extends distally toward base of, but not including, the glans
  • Superficial: Colle's fascia
  • Deep: Buck's fascia

Urogenital triangle - within superficial pouch between superficial perineal fascia (derivative of Scarpa's fascia) and perineal membrane (deep fascia)

  • Superior: perineal membrane (inferior fascia of the urogenital diaphragm
  • Inferior: superficial perineal fascia
  • Anterior: open into scrotum
  • Posterior: posterior free edge of urogenital diaphragm, superficial perineal fascia
  • Lateral: conjoint rami
  • Medial: not restricted

Extravasation into the ischiorectal fossa? - NO

  • Limited by superior fascia of UG diaphragm
  • Limited by superficial perineal fascia (attached to posterior free edge of UG diaphragm and conjoint rami)

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Transverse Colon - September 16, 2010

Discuss the anatomy of the transverse colon. Include structure, support, relationships, innervation, vasculature, and lymphatics. (12 pts)

General comments

  • The transverse colin is an intraperitoneal segment of the large bowel. It spans from the right colic flexure to the left colic flexure. Surgical access to the lesser sac is provided by the gastrocolic ligament. The transverse colon divides the greater sac into supracolic and infracolic compartments.

Structure

  • Layers - from inner to outer
    • mucosa (columnar epitheleum) - no villi in large intestine
    • submucosa (vascular and submucosal nerve plexuses) - padding between mucosa and muscular layer
    • tunica muscularis - inner circular and outer longitudinal smooth muscle, myenteric plexus, peristalsis
    • mesothelium and connective tissue
    • serosa - visceral peritoneum covers the transverse colon except at the attachment of transverse mesocolon
  • Teniae coli - 3 longitudinal bands of smooth muscle
  • Haustra coli - sacculations caused by the teniae coli being shorter than the gut tube
  • Appendices epiploicae - fat appendages hanging from the teniae
  • Caliber is generally larger than the small intestine

Support

  • Right
    • superior aspect of retroperitoneal ascending colon, cradled by right lobe of liver
    • right hepatocolic ligament
  • Middle
    • transverse mesocolon attaches to posterior abdominal wall crossing right kidney, duodenum, IVC, aorta, pancreas, left kidney
    • gastrocolic ligament provides anchoring to the stomach
  • Left
    • phrenicocolic ligament

Relationships

  • Right - level of L2
    • Superior - liver, gallbladder, descending duodenum
    • Inferior - coils of jejunum and ileum
    • Anterior - costal margin, diaphragm, liver
    • Posterior - diaphragm, right kidney, inferior vena cava, pancreas, quadratus lumborum
    • Medial - itself
    • Lateral - liver, right paracolic gutter, hepatorenal recess
  • Middle - level of L1-2
    • Superior - stomach, gastrocolic ligament, liver, lesser sac
    • Inferior - coils of jejunum and ileum
    • Anterior - greater omentum, costal margin, diaphragm, falciform ligament
    • Posterior - pancreas (head, body, and tail), horizontal duodenum, aorta, superior mesenteric artery, intestinal mesentery
    • Lateral left - left colic flexure (see below)
    • Lateral right -right colic flexure (see above)
  • Left - level of T12-L1
    • Superior - spleen, diaphragm
    • Inferior - jejunum, descending colon, left paracolic gutter
    • Anterior - diaphragm
    • Posterior - diaphragm, left kidney, quadratus lumborum
    • Lateral - phrenicocolic ligament, superior aspect of left paracolic gutter
    • Medial - itself

Innervation

  • Right Side
    • Parasympathetic
      • Preganglionic
        • vagus nerves * preganglionic pathway - vagus nerves, superior mesenteric ganglion (no synapse), superior mesenteric plexus, right and middle colic arteries
      • Postganglionic
        • enteric ganglia at the target
        • cell bodies in submucosal layer - postganglionic fibers contribute to submucous plexus, enteric plexus
    • Sympathetic
      • Preganglionic
        • cell bodies within intermediolateral cell column (IMLCC) of T10-11
        • preganglion fiber path - ventral root to spinal nerve, to ventral ramus, white ramus communican, thoracic sympathetic trunk, thoracic splanchnic nerves, lesser splanchnic nerve
      • Postganglionic
        • cell bodies in the superior mesenteric ganglion
        • postganglionic fiber pathway - superior mesenteric plexus, right colic artery, middle colic artery, enteric plexus
    • Visceral Afferent
      • High threshold (pain)
        • follow sympathetic preganglionic and sympathetic postganglionic pathways
      • Low threshold (homeostatic)
        • follow the vagus nerves
  • Left Side
    • Parasympathetic
      • Preganglionic
        • pelvic splanchnics
        • preganglionic pathway - IMLCC S2-4, pelvic splanchnics, inferior hypogastric plexus, left hypogastric nerve, sigmoid mesocolon, retroperitoneal along medial margin of descending colon, left transverse mesocolon
      • Postganglionic
        • enteric ganglia at the target
        • cell bodies in submucosal layer - postganglionic fibers contribute to submucous plexus, enteric plexus
    • Sympathetic
      • Preganglionic
        • cell bodies within intermediolateral cell column (IMLCC) of L1-3
        • preganglion fiber path - ventral root to spinal nerve, to ventral ramus, white ramus communican, lumbar sympathetic trunk, lumbar splanchnic nerves, aoric plexus, inferior mesenteric ganglia (synapse here)
      • Postganglionic
        • cell bodies in the inferior mesenteric ganglia
        • postganglionic fiber pathway - inferior mesenteric plexus, left colic artery, enteric plexus
    • Visceral Afferent
      • High threshold (pain)
        • follow sympathetic preganglionic and sympathetic postganglionic pathways
      • Low threshold (homeostatic)
        • follow parasympathetic preganglionic pathway (see parasympathetic preganglionic pathway)

Vasculature - provided by the arteriovenous supply of midgut and hindgut, venous drainage is into portal system

  • Right
    • Right colic artery/vein from superior mesenteric artery/vein
      • retroperitoneal up to right colic flexure
      • contributes to marginal artery/vein
  • Middle
    • Middle colic artery/vein from superior mesenteric artery/vein
      • travels through to transverse mesocolon
      • contributes to marginal artery/vein
  • Left
    • Left colic artery/vein from inferior mesenteric artery/vein
      • retroperitoneal up to left colic flexure
      • contributes to marginal artery/vein

Lymphatic drainage

  • General
    • intestinal nodes to central nodes (superior and inferior mesenteric nodes) to intestinal lymph trunks to cysterna chyli
  • Right
    • paracolic nodes to superior mesenteric nodes
  • Middle
    • paracolic nodes to superior mesenteric nodes
  • Left
    • paracolic nodes to inferior mesenteric nodes

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Diaphragm - September 17, 2009

Review the anatomy of the diaphragm including the parts of the diaphragm, apertures, pathways of structures coursing between the thorax and abdomen, vasculature, fascia, lymphatic drainage, relationships, and innervation. (12 pts)

General Comments

  • Separates the abdomen from the thorax
  • Convex toward the thorax
  • 10 cm movement with maximum inspiration
  • right dome at 6th costochondral joint level on expiration
  • Left dome one rib lower than right
  • central tendon is thin aponeurosis of trifoliate shape
  • cura origin blends with the anterior longitudinal ligament

Parts of the diaphragm

  • central tendon - central aspect of diaphragm
  • tendinous site of attachment for coronary ligament (and pericardial sac)
  • sternal portion - xiphoid process upward and backward to central tendon
  • costal portion - inner surface of costal cartilages 7, 8, 9 bony 10, 11, 12
  • lumbar portion - from the arcuate ligaments and lumbar vertebrae by way of the cura
  • domed peripheral muscular part
  • right crus of diaphragm
    • contributes to esophageal hiatus
    • inferior insertion extends to L3 anterior vertebral body
  • left crus of diaphragm
    • inferior insertion extends to L2
  • median arcuate ligament
    • fibrous ligamentous arch connecting diaphragmatic cura
    • forms anterior boundary of aortic hiatus
  • medial arcuate ligament
    • posterior attachment of diaphragm to fascia of psoas major
    • vertebral level L1/L2
  • lateral arcuate ligament
    • posterior attachment of diaphragm to fascia of quadratus lumborum
    • attachment to anterior aspect of the transverse process of L1
    • attachment to the mid-12th rib
    • vertebral level L1/L2
  • lumbocostal trigone (arch) (Bochdalek's triangle) (vertebrocostal trigone)
    • thinning of muscle usually on the left and immediately superior to the lateral arcuate ligament
    • site of herniation
    • surgically at risk during renal surgery

Apertures

  • aperture for the IVC (inferior vena cava) at vertebral level T8 * transmits the IVC and branches of the right phrenic nerve
  • aperture for the esophagus (esophageal hiatus) at vertebral level T10
    • encloses by insertion of right crus into central tendon
    • phrenoesophageal ligament (transversalis fascia) seals between cavities
    • transmits the esophagus, anterior and posterior vagal nerve trunks, esophageal branches of the left gastric vessels
  • aperture for the aorta (aortal hiatus) at vertebral level T12
    • boundaries - anterior is median arcuate ligament, lateral left is left crus, lateral right is right crus, posterior is the vertebral body of T12 and the anterior longitudinal ligament
    • transmits aorta, thoracic duct, lymph ducts, azygos vein, hemiazygos vein, ascending lumbar vein

Pathways of structures coursing between thorax and abdomen

  • IVC enters abdomen through hiatus for IVC
    • branch of phrenic n.
  • esophagus enters abdomen through esophageal hiatus at T10
    • anterior and posterior vagal nerves
    • esophageal a. v. from left gastric a. v.
  • aorta enters abdomen through aortic hiatus at T12
    • thoracic duct
    • ascending lumbar veins or azygos v.
  • piercing the cura of diaphragm
    • greater, lesser, least splanchnic nn
  • medial to the medial arcuate ligament
    • sympathetic trunk and psoas major
  • posterior to the lateral arcuate ligament
    • subcostal nerve and quadratus lumborum
  • anterior diaphragm is pierced by superior epigastric vessels

Relations (limited to abdomen) - consider that the diaphragm is domed shaped

  • Anterior aspect of diaphragm - right side
    • posterior lies the liver, gall bladder, and duodenal cap
  • anterior diaphragm - left side
    • posterior - greater sac, lesser omentum, stomach, greater omentum, transverse colon
  • superior diaphragm - right side
    • inferior - liver, IVC
  • superior diaphragm - left side
    • inferior - aorta, stomach, and spleen
  • posterior diaphragm - right side
    • anterior - left kidney and suprarenal g. and the liver
    • lateral - greater, lesser, least splanchnic nerves, celiac and superior mesenteric ganglia lie of the cura
  • posterior diaphragm - left side
    • anterior - pancreas, duodenum, stomach, transverse colon, spleen, kidney and suprarenal g., lesser sac
  • much of the inferior diaphragm is covered with peritoneum
    • the resulting peritoneal spaces between diaphragm and liver, stomach, and spleen are the subphrenic recess
  • ligaments
    • coronary ligament
    • leinorenal ligament
    • suspensory ligament of the duodenum
    • phrenicocolic ligament

Vasculature and Lymphatic Drainage

  • anterior peripheral by musculocutaneous a. v. and anterior intercostal a. v.
  • posterior peripheral by posterior intercostal a. v.
  • pericardiacophrenic vessels
  • superior phrenic a. v.
  • inferior phrenic a. v. - central tendon
    • right vein drains into IVC whereas the left drains into the left renal vein
  • parasternal nodes
  • posterior mediastinal nodes
  • lumbar nodes

Innervation

  • motor supply entirely by phrenic nerve
  • peripheral sensory by intercostal n.
  • central tendon motor and sensory by phrenic n.

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Rectum and Anal Canal - September 17, 2009

Review the anatomy of the rectum and anal canal. Include peritoneal relationships, vasculature, lymphatic drainage, innervation, and relationships to surrounding structures and spaces. (12 pts)

General Anatomy of the Rectum

  • rectosigmodal junction at S3 extending to tip of coccyx and ending at anorectal junction (pelvic floor)
  • ends 2cm anterior and slightly inferior to the tip of the coccyx
  • passes through pelvic diaphragm before anorectal junction
  • 12 cm long with two convexities to right and one to left
  • transverse folds - two on the right and one on the left (this is variable)
  • teneia coli broaden to form longitudinal muscle layer
  • no haustra or appendices epiploica
  • smooth mucosa
  • distensible at the rectal ampulla

Peritoneal coverings and relations

  • upper 1/3 covered anterior and lateral
  • middle 1/3 covered anterior
  • lower 1/3 not peritonealized
  • peritoneal pouches and fossa
  • ant: rectouterine or rectovesical pouch
  • lateral: pararectal fossae

Relations to surrounding structures

  • Anterior - bladder, vagina, uterus, prostate, seminal vesical, vasdeferens, ureters
  • Posterior - presacral space, sacrum, sacral foramina, sacral plexus, sacral sympathetic trunk, piriformis, middle and lateral sacral arteries
  • lateral (left and right) - inferior hypogastric plexus, pelvic wall and associated structures, appendix on right
  • Superior - sigmoid colon, false pelvis
  • Inferior - anal canal, pelvic floor

Ligaments and support

  • Rectovesical - part of the pubosacral ligamentous complex (derived from pelvic visceral fascia)
  • Rectosacral - part of the pubosacral ligamentous complex (derived from pelvic visceral fascia)

Innervation (no somatic for rectum proper)

  • sympathetic - inhibitory to muscles of the rectal wall
    • Preganglionic: IMLL L1-3 - white rami - lumbar sympathetic trunk - lumbar splanchnics - aortic plexus - inferior mesenteric ganglion
    • Postganglionic: inferior mesenteric plexus - superior rectal aa, right and left hypogastric nerves to rectal plexus
  • parasympathetic - relax internal anal sphincter, glandular secretion
    • Preganglionic: pelvic splanchnic nerves leave ventral rami of S2-4 spinal nerves to enter the pelvic plexus on either side of the rectum (inferior hypogastric plexus)
    • an extension of the pelvic plexus either independently or via the left hypogastric nerve contributes to rectal plexus
    • postganglionic: cell bodies and fibers are located in enteric (intrinsic) ganglia
  • Visceral afferent fibers
    • low threshold (homeostatic) follow parasympathetic pathways
    • high threshold (pain) follow sympathetic pathways

Vasculature Supply

  • superior rectal aa pair on lateral posterior rectum - derived from single continuation of inferior mesenteric a - provides superior aspect of rectum
  • superior rectal vein - drains most of the entire venus plexus of the rectum
  • middle rectal artery - from internal iliac - provides inferior aspect of rectum
  • inferior rectal artery - from pudendal artery - anastomosis with middle rectal artery
  • median sacral artery at the posterior aspect of the anorectal junction
  • rectal venous plexus drains to prostatic plexus or uterovaginal plexus
  • inferior rectal and superior rectal veins form an interface between caval and portal drainages
  • epirectal lymph nodes drain superior toward upper lumbar nodes near the inferior mesenteric nodes
  • pararectal nodes drain laterally into internal iliac nodes

General Anatomy of the Anal Canal

  • begins at anorectal junction and ends at anal verge
  • 2.5 - 5 cm long
  • anterior flexion by puborectal sling (puborectalis)
  • transisition from cuboidal to squamous epithelium at the dentate line
  • layers - inner epithelium, vascular subepithelium, internal anal sphincter, external anal sphincter, fibromuscular support tissue
  • anterior attachment to perineal body
  • posterior attachment to anococcygeal raphe
  • surrounded by ischiorectal fat
  • rectal circular muscle becomes internal anal sphincter
  • puborectalis is continuous with external anal sphincter
  • anal columns end at anal valves
  • anal valves and sinuses mark the dentate line and the anorectal junction
  • stratified squamous epithelium inferior to dentate line
  • stratified columnar epithelium superior to dentate line
  • anal tranisition zone (ATZ) not same as dentate line but may include it
  • haemorrhoids of the anal cushions are superior to dendate line and may reflect portal hypertension

Innervation of the Anal Canal

  • distal to dentate line
    • somatic motor and sensory by pudendal nerve
    • defined pain
  • proximal to dentate line
    • visceromotor by autonomic nervous system (see above for rectum)
    • visceral afferent follow autonomic pathways (see above for rectum)
    • "dull ache"
  • external anal sphincter by inferior rectal branches of the pudendal nerve
  • internal anal sphincter by autonomic nerves

Vasculature of the Anal Canal

  • proximal - superior rectal artery/vein and median sacral artery/vein
  • distal - inferior rectal artery/vein from the internal pudendal artery/vein
  • proximal lymphatic drainage - upper lumbar nodes
  • distal lymphatic drainage - superficial inguinal nodes and internal iliac nodes

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Spermatic Cord and Indirect Inguinal Hernia - September 17, 2009

Review the anatomy of the spermatic cord. Include contents, coverings, fascial boundaries, innervation, vasculature, lymphatics, and relationships. Discuss the pathway and location of an indirect inguinal hernia that has descended into the scrotum. (12 pts)

General Comments

  • The spermatic cord is the pedicle of testis. Beginning at the deep ring, the spermatic cord transmits the contents of the deep ring from the abdominopelvic cavity to the scrotum.
  • The pathway from the deep ring to the scrotum marks the "descent" of the testis.
  • A peritonealized surface of the testis causes a trailing diverticulum know as the processes vaginalis.
  • Applied to the anterior aspect of the testis is the visceral layer of tunica vaginalis.
  • The deep ring marks the beginning of the inguinal canal and is located: at the midinguinal point; lateral to the inferior epigastric artery; and slightly more than 1 cm superior to the inguinal ligament.
  • At the deep ring the spermatic cord receives the internal spermatic fascia derived from transversalis fascia. Within the inguinal canal the internal oblique contributes the cremasteric fascia.
  • The cord exits the inguinal canal by way of the superficial ring.
  • The superficial ring, a defect in the external oblique aponeurosis, contributes the external spermatic fascia.
  • The testis, at the distal extent of the cord, ultimately resides within the scrotum. It is tethered to the most inferior aspect of the scrotum by the scrotal ligament.
  • The external spermatic fascia (deep fascia) is opposed to dartos fascia (superficial fascia).

Internal Spermatic Fascia. Structures that pass through the deep ring were retroperitoneal and reside within the internal spermatic fascia derived from transversalis fascia.

  • processes vaginalis - a trailing diverticulum of peritoneum that accompanies the testis during the "descent."
  • Distally, within the scrotum, the processes vaginalis opens into the tunica vaginalis
  • Extraperitonial connective tissue
  • Testicular artery - paired branches from lumbar aorta near renal arteries
  • Testicular vein - proximally the testicular vein consists of 3-4 veins
  • Distally the testicular surrounds the testicular artery forming the pampinifrom plexus veins numbering 10 to 12 veins
  • Left testicular vein drains into left renal vein and the right testicular vein drains into the IVC near the renal artery
  • Testicular lymphatics - provide drainage to upper lumbar nodes, to lumbar lymph ducts, to cysterna chyli
  • Testicular autonomic plexus - sympathetic preganglionic cell bodies in IMLCC T10(11-12)
    • Symmpathetic postganglionic cell bodies in superior mesenteric ganglion
    • Parasympathetic preganglionic fibers derived from the vagus nerve
  • Afferent "pain" fibers following sympathetic pathways to spinal levels T10(11-12)
  • Vas deferens - under sympathetic control, the walls (2-3 mm thick) of the vas deferens contract to discharge spermatozoa
  • Within the cord the Vas deferens lies posterior to the testicular artery
  • Distally, the Vas deferens forms the tail of the epididymis at the posterior inferior pole of testis
  • Further distally the tail gives way to the body and then to the head of the epididymis at the posterior superior pole
  • Deferential artery - branch of the internal iliac artery vascularizes the vas deferens and anastomoses with the testicular artery
  • Deferential autonomic plexus - derived from the superior/inferior hypogastric autonomic plexus to prostatic plexus
    • Parasympathetic preganglionic fibers possibly derived from pelvic splanchnics (S2-4)
    • Afferent "pain" fibers following sympathetic pathways to spinal levels T10(11-12)
  • Deferential lymphatics - drainage to internal iliac nodes, to lumbar lymph ducts, to cysterna chyli
  • Genital branch of genitofemoral nerve - mediates efferent component of cremasteric reflex
  • Cremesteric artery - branch of inferior epigastric artery vascularizes the tunics

The cremesteric fascia is superficial to the internal spermatic fascia and deep to the external spermatic fascia

  • Derived from internal oblique muscle, the cremesteric fascia contributes to the cord within the inguinal canal
  • Genital branch of the genitofemoral nerve - provides somatic motor supply
  • Cremesteric artery - branches provide vascularization to the cremesteric fascia

The external spermatic fascia is superficial to the cremesteric fascia and is the outer most tunic

  • Derived from the external oblique, the external spermatic fascia extends to the cord beyond the superficial ring
  • Within the scrotum the external spermatic fascia is deep to dartos tunic

Path of indirect inguinal hernia

  • An indirect hernia follows the embryologic "descent" of the testis indirectly out the superficial ring by way of the deep ring.
  • A patent processes vaginalis allows herniated material to pass through the deep ring lateral to the inferior epigastric artery
  • Herniated material passes through the inguinal canal and out the superficial ring - superior and medial to pubic tubercle
  • Distally, the hernia is arrested by the tunica vaginalis
  • In the case of herniated intestine, visceral peritoneum is directly opposed to visceral and parietal tunica vaginalis
  • Palpation of the hernia occurs at the anterior aspect of the testis within the scrotum
  • The long and curvaceous path of an indirect hernia make strangulation a distinct possibility

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Abdomen, Pelvis, and Perineum - Written Examination September 22: Part V - Essay

*Note: This is an outline of topics to be covered. It is not the "answer key." It is an answer guide. *

External Oblique Muscle

Define the origin(s), insertion(s) and relationships of the external abdominal oblique muscle, including any aponeurotic/derivations/ligamentous terminations. Discuss the innervation, vasculature, and lymphatics of this muscle.
  • The external oblique is a digastric muscle having the linea alba as its central tendon. Each belly is quadralateral in shape. It has superior attachments to the external surface of the ribs. Inferior attachments to the ilium and pubis. Anterior attachments to the rectus sheath and linea alba. The posterior aspect of the external oblique has a free border near the lateral extent of the thoracolumbar fascia.
  • Origins
    • Anterior, lateral, and external surfaces of Ribs 5 - 12
    • Paired digastric muscle with linea alba as central tendon
  • Insertions
    • Anterior and lateral iliac crest
    • Anterior superior iliac spine
    • Inguinal ligament - free edge of the aponeurosis
    • Pubic tubercle, crest, and symphysis
    • Pectin line by way of pectineal ligament
  • Relationships
    • Continuous with external intercostals and forms outer muscle layer of anterior abdominal wall
    • Interdigitates with serratus anterior and with latissimus dorsi
    • Superficial to the internal oblique muscle
    • Deep to tela subcutanea, campers fascia, and Scarpa's fascia
    • Attachments of Scarpa's fascia define potential space, fundiform ligament
    • Inguinal ligament provides site of attachment for the internal oblique and for the transversus abdominis
  • Derivations
    • Rectus sheath
      • anterior lamina
      • linea semilunaris
    • Linea alba
    • Lumbar triangle
    • Inguinal canal
      • Inguinal ligament - inferior
      • Aponeurosis - anterior
      • Arcades - superior
      • Superficial ring - distal opening
    • Superficial inguinal ring
      • Inguinal ligament
      • Medial crus
      • Lateral crus
      • Intercrural fibers
      • Reflected inguinal ligament
      • External spermatic fascia
    • Femoral ring
      • Inguinal ligament - anterior
      • Lacunar ligament - medial
      • Pectineal ligament - Posterior
  • Innervation
    • Lower 6 intercostal nerves and the subcostal nerve
    • Iliohypogastric nerve
  • Vasculature
    • Lower 6 intercostal arteries and the subcostal artery
    • Lumbar arteries
    • Iliolumbar artery
    • Deep circumflex iliac arteries
    • Inferior and superior epigastric arteries
    • Superficial epigastric and superficial circumflex iliac arteries and veins
  • Lymphatics
    • Below the level of the umbilicus there is superficial drainage into superificial inguinal nodes by way of lymph vessels traveling with superficial epigastric and superficial circumflex iliac veins.
    • Above the level of the umbilicus there is superficial drainage into parasternal, pectoral, subscapular, and axillary nodes.
    • Deep drainage is into common iliac nodes (deep circumflex iliac vessels and inferior epigastric vessels)
    • para-aortic nodes (lumbar and intercostal vessels), intercostal nodes, internal iliac nodes (iliolumbar vessels)
    • Parastenal nodes (superior epigastric vessels)

Stomach

Review the structure of the stomach. Include the anatomy of the stomach, supporting elements, vasculature, lymphatic drainage, innervation, and relationships to surrounding structures and spaces.
  • General
    • The stomach is located in the left upper quadrant of the abdominal cavity.
    • Extends toward the right to reach the level of the umbilical region
    • Adult capacity of about 1500 ml
    • Intervenes between the esophagus and the duodenum
    • The most superior extent of the fundus is at T9
    • The most inferior extent of the antrum is at L2
  • External Structure
    • Cardiac incisor
    • Body
    • Fundus - projects into the left dome of the diaphragm as high as the 5th intercostal space
    • Antrum
    • Pyloric canal - 1-2 cm in length
    • Pylorus - sphincter into duodenal cap
    • Lesser curvature - to the right between the cardiac incisura and the pyloric sphincter, lesser omentum, ventral mesentery
    • Greater curvature - gastrolieno ligament, greater omentum, dorsal mesentery, as high as the 5th intercostal space
  • Internal Structure
    • Gastric rugal folds of mucosa
    • Longitudinal folds
    • Pyloric orifice
  • Support
    • Lesser omentum (hepatogastric and hepatoduodenal ligament)
    • Greater omentum - gastrocolic ligament
    • Gastrolieno ligament
    • Lienorenal ligament
    • Esophageal hiatus
  • Vasculature
    • Lesser curvature - right and left gastric arteries from hepatic artery and celiac trunk, lesser omentum
    • Cardiac region - esophageal artery from left gastric, vein is implicated in esophageal varices in the case of portal hypertension
    • Fundus - short gastric arteries from splenic artery, gastrolieno ligament
    • Greater curvature - left and right gastroepiploic arteries from splenic and gastroduodenal arteries, greater omentum
    • Venous drainage directly into portal vein and indirectly by way of superior mesenteric vein
  • Lymphatic drainage
    • Nodes named for the arterial supply drain into celiac nodes
    • Splenic nodes, pancreatic nodes, infrapyloric nodes,
  • Innervation
    • Preganglionic parasympathetic - vagus nerve branches to celiac plexus follow arterial supply to the stomach
    • Postganglionic parasympathetic - intrinsic ganglia within the stomach
    • Preganglionic sympathetic - IMLCC of T5-9 ventral root - spinal nerves - white ramus communican - thoracic sympathetic trunk - splanchnic nerves - greater splanchnic nerve - pierce right crus diaphragm - enter celiac ganglion
    • Postganglionic sympathetic - celiac ganglion - celiac plexus - follow arterial supply to stomach
    • Sensory (low threshold homeostatic) celiac plexus to anterior and posterior vagal trunks
    • Sensory (high threshold pain) celiac plexus through celiac ganglion - greater splanchnic nerves - splanchnic nerves - sympathetic trunk - ramus communican - spinal nerve - dorsal root - cord levels T5-9
    • Superior mesentric ganglia and the plexus are sometimes said to contribute. Thus T10-11 levels may be involved.
  • Relationships
    • Anterior surface
      • Faces greater sac
      • Left - diaphragm, spleen, intercostal spaces 5 - 9
      • Right - quadrate lobe of liver
      • Inferior - transverse colon
      • Superior - dome of the diaphragm
    • Posterior surface
      • Faces lesser sac
      • Right - left crus diaphragm and diaphragm proper, left inferior phrenic artery and suprarenal gland,
      • Intermediate posterior - pancreas, splenic artery, transverse colon
      • Left - left colic flexure, spleen, superior pole left kidney
    • Spaces
      • Subphrenic space

Ovary

Discuss the anatomy of the ovary and include relationships (6 directions), structure, surfaces, supports, vasculature, innervation, and lymphatic drainage.
  • Structure
    • The ovary is roughly cylindrical about 3 cm long and 1 cm in diameter.
  • Surfaces
    • The visceral peritoneum covering the ovary gives way to a specialized germinal epithelial cell layer. *The egg is able to penetrate this layer and enter the peritoneal cavity.
  • Support
    • The ovary is suspended from the posterior lamina of the broad ligament by the mesovarium -- a peritoneal ligament.
    • Supporting the superior pole of the ovary to the pelvic brim is the suspensory ligament of the ovary.
    • Supporting the inferior pole of the ovary to the lateral uterus is the ovarian ligament.
  • Vasculature
    • The arterial supply is mostly from the ovarian arteries. These are paired arteries arising from the anterolateral surface of the aorta near the level of the third lumbar vertebra. The ovarian veins arise from the IVC on the right and the left renal vein on the left. Additional blood supply is by ascending branches of the uterine vessels (ovarian br.) that anastomose with the ovarian vascular supply.
  • Innervation
    • Parasympathetic preganglionic cell bodies are located in the central gray of the spinal cord (IMLCC) at levels S2-4. Preganglionic fibers enter the inferior hypogastric plexus by way of the pelvic splanchnic nerves. The inferior hypogastric plexus contributes a uterine plexus and then to the ovarian plexus. Postganglionic parasympathetic cell bodies are located in intrinsic ganglia of the ovary. The above pathway assumes that the uterovaginal plexus reaches the ovary. This is not known for certain. Parasympathetic pregangionic contributions from the vagus n. may also follow the ovarian plexus.
    • Sympathetic preganglionic cell bodies are located in the interomedial lateral cell column at cord levels T10 (and perhaps T11-12). Preganglionic fibers follow the lesser and least splanchnic nerves to aortic ganglia near (and including) the superior mesenteric ganglion and the aorticorenal ganglion. Postganglionic fibers from these ganglia enter the aortic plexus and extend along the ovarian artery as the ovarian plexus. Visceral afferent pathways follow the sympathetic pathways up to the T10 spinal level. Additional visceral pathways follow parasympathetic pathways back to the S3-4 spinal levels.
  • Lymphatic drainage
    • Lymph drainage is primarily along the embryological decent of the ovary. This includes upper lumbar nodes in the vicinity of the renal arteries. Much of the vascular supply reaches the ovary through the suspensory ligament.
    • Lymph drainage to superficial inguinal nodes follows the ovarian and round ligament.
    • Internal iliac nodes and ovarian fossa
  • Relationships
    • superior to the ovary is the pelvic brim and suspensory ligament
    • inferior to the ovary is the uterine wall and the ovarian ligament
    • anterior to the ovary is the broad ligament, uterine tube, and fimbria of uterine tube
    • posterior to the ovary is the rectum and pelvic floor
    • medial to the ovary is the pararectal fossa, rectouterine pouch, fundus of the uterus
    • lateral to the ovary is the ovarian fossa (internal iliac a. and ureter), psoas major muscle, and obturator n.

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Written Examination Part IV. (36 pts) - Essay: Abdomen, Pelvis, and Perneum (September 20, 2007)

Lesser Sac (Omental Bursa)

Define the boundaries (including spaces and/or recesses) of the lesser sac including . Explain why damage to the stomach would produce sharp pains in the abdomen. Account for food particles also detected in the greater sac despite erosion of the posterior wall of the stomach. Discuss the pathway of materials that pass into the greater sac, and the location of these fluids/food contents with respect to body position. (12 pts)
  • General comments
    • The lesser sac is a diverticulum in the superior region of the peritoneal cavity. Communication with the greater sac is via the epiploic foramen. For the most part, the lesser sac is posterior to the stomach and liver, anterior to the pancreas and diaphragm, superior to the duodenum, pancreas, and transverse mesocolon, inferior to the liver and diaphragm, left of the caudate, and right to the gastroleino and leinorenal ligs.
  • Superior recess - posterior to liver, begins at epiploic foramen
    • anterior - caudate lobe of liver and lesser omentum
    • posterior - diaphragm
    • superior - diaphragm
    • inferior - lesser recess
    • right - liver, ligamentum venosum
    • left - splenic recess
  • Inferior recess - inferior ot the right gastropancreatic fold (common hepatic a.)
    • anterior - hepatoduodenal ligament, duodenum, gastrocolic ligament
    • posterior - pancreas, tail of pancreas enters leinorenal ligament
    • superior - superior recess
    • inferior - transverse mesocolon
    • right - liver
    • left - gastroleino ligament
  • Splenic recess - left of gastroepiploic fold (left gastric a.)
    • anterior - stomach, gastrocolic ligament (greater omentum)
    • posterior - aorta, left suprarenal gland, upper pole left kidney, splenic a., diaphragm
    • superior - liver and diaphragm
    • inferior - inferior recess
    • right - caudate lobe, superior recess
    • left - gastroleino and leinorenal ligaments
  • Epiploic foramen - communication between lesser and greater sacs
    • anterior - hepatoduodenal ligament
    • posterior - inferior vena cava
    • superior - caudate lobe liver
    • inferior - duodenum
    • right - opening into hepatorenal recess and right paracolic gutter
    • left - lower recess of lesser sac
  • Pathway of Materials?
    • Person rolls to the right - contents of lesser sac enter the greater sac via the epiploic foramen
    • Person returns to supine - contents enter the hepatorenal recess
    • Person stands - contents follow the right paracolic gutter to the pelvic basin and the rectouterine or rectvesical pouch
    • General discussion of abdominopelvic gutters
  • Somatic afferent innervation
    • parietal peritoneum of the posterior wall innervated by thoracoabdominal nerves
  • Why sharp pain?
    • Irritation of the parietal peritoneum of the posterior wall activates somatic afferent activity in the thoracoabdominal nerves (intercostals, subscostals, iliohypogastric, ilioinguinal) and possibly phrenic nerve.
  • Vascular supply of the Walls - vascular supply is by regional aa and vv (optional)
    • posterior - splenic av
    • anterior - common hepatic, right gastric, left gastric, aa
    • inferior - right and left gastroepiploic aa vv, supra- and retroduodenal aa vv
    • superior - inferior phrenic av
    • left - short gastric aa vv
    • right - right and left gastric aa vv
  • Lymphatic drainage of the Walls - follows vascular supply (optional)
    • paraaortic nodes to lumbar trunks to cysterna chyli
    • diaphragmatic border involves mediastinal and axillary nodes (anterior wall vasculature)
  • Autonomic Innervation to the Walls (optional)
    • sympathetic preganglonics - mostly from greater and lesser splanchnic nerves (cell bodies in imlcc of T5-11)
    • sympathetic postganglionics - mostly from celiac plexus (cell bodies in celiac ganglion)
    • parasympathetic preganglionics - from vagus nerve (cell bodies in dorsal motor nucleus of vagus nerve)
    • parasympathetic postganglionics - intrinsic ganglia
  • Visceral afferent innervation from the Walls (optional)
    • "pain" follows sympathetic pathways to spinal levels T5-11

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Course and Branches of the Internal Pudendal Artery

Discuss the course and branches of the internal pudendal artery in the pelvis, gluteal region, and perineum. Please include anatomical relationships of the artery, fascial layers involved, as well as spaces/recesses encountered by the internal pudendal artery and its branches. (12 pts)
  • General Comments and Overview
    • The internal pudendal artery arises from within the pelvic and a branch of the internal iliac artery. It leaves pelvis via greater sciatic foramen to enter gluteal region. The short gluteal course loops posterior to ischial spine. Inferior the the spine the artery enters the ischiorectal fossa via lesser sciatic foramen.
  • Internal pudendal artery enters pudendal canal
    • osseofibrous canal formed by obturator internus fascia and falciform edge of ischial tuberosity
    • elaborates inferior rectal branch just before canal or from within canal
      • courses inferior, medial, and anterior through fatty tissue toward anorectal area
    • exits canal at posterior free edge of urogenital diaphragm within ischiorectal fossa
  • elaborates terminal branches
    • superficial perineal a. - posterior scrotal (labial)
    • deep perineal a. - pierces superficial perineal fascia to enter superficial pouch o to muscles of superficial and deep pouches
    • dorsal a. of the clitoris or penis
      • runs along conjoint ramus within anterior recess ischiorectal fossa.
      • pierces tranverse perineal ligament to enter onto dorsum of penis or clitoris
      • deep to Buck's fascia and superficial to tunica albuginea
      • resides lateral to deep dorsal vein and medial to dorsal nerve
      • other descriptions indicate a course through the superficial and deep pouches
        • both descriptions are verified on dissection
    • deep artery
      • travels partway along conjoint ramus within anterior recess of ischiorectal fossa
      • pierces superior fascia of urogenital diaphragm to enter the deep pouch
      • pierces inferior fascia of urogenital diaphragm at tunica albuginea of crus
      • pierces crus to enter corpora cavernosum and course distally

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Pelvic Diaphragm

Discuss the anatomy of the pelvic diaphragm. Include structure, fascial coverings, spaces, vascularization, innervation, lymphatic drainage and relationships. (12 pts)
  • Structure and fascial coverings of the pelvic diaphragm
    1. The pelvic diaphragm is a thin sheet of muscle. The urethra, vagina, and anal canal pass through the pelvic diaphragm at the urogenital hiatus. Posterior to the vagina and anterior to the anal canal, the urogenital hiatus is filled by the perineal body and the pubococcygeus muscle. The pelvic diaphragm functions in micturation and defecation by controlling intra-abdominal pressure and the anatomical properties of functional sphincters -- uvula and puborectal sling.
    2. The anterior aspect of the pelvic diaphragm is made up of the pubococcygeus, iliococcygeus, and the puborectalis. Collectively, these three muscles constitute the levator ani. Its lateral halves slope inferiorly medially from the arcus tendineus to meet at the midline of pelvic floor. The pubococcygeus and especially the ilococcygeus, upon contracting, raise the pelvic floor. These two muscles are tethered to the coccyx by the anococcygeal raphe and insert upon the lateral aspects of the urethra, prostate, vagina, and anal canal.
    3. The puborectalis arises from the pubic bones near the superior aspect of the symphysis. It lies on the inferior surface of the pubococcygeus muscle. Posteriorly, the puborectalis muscle circles the anorectal junction. It is not tethered by the anococcygeal raphe. Thus, when contracted, the puborectalis pulls the rectum anterior and thereby promotes fecal continence.
    4. The posterior wall of the pelvic diaphragm is defined by the ischiococcygeus muscle. This muscle is not antomically favored to directly elevate the pelvic and, thus, is not included as part of levator ani. However, the ischiococcygeus muscle, by virtue of its attacments to the ischial spine and the coccyx acts of approximate these two structures and indirectly assists in elevating the pelvic floor.
    5. The superior surface of the pelvic diaphragm is covered by parietal pelvic fascia. This fascia is continuous with the transversalis fascia of the abdominal cavity. The inferior surface of the pelvic diaphragm is covered by the inferior fascia. This fascia is continuous with deep fascia of the perineum.
  • Relations of the pelvic diaphragm
    1. Superior - immediate is pelvic visceral fascia then the pelvic viscera and the abdominal cavity; retropubic space, presacral space, paravesical space, pubosacral ligamentous complex
    2. Inferior anterior - superior fascia urogenital diaphragm
    3. Inferior posterior - posterior recess of ischiorectal fossa including fat, gluteus maximus, and perineal skin
    4. lateral - arcus tendineus and obturator internus fascia (oburator nerve, external iliac artery and vein)
    5. anterior - superior aspect of the conjoint rami near pubic symphysis
    6. Posterior - piriformis muscle and sacrum (sacral plexus, sacral sympathetic trunk, middle sacral artery, effluents of sciatic foramina)
  • Vasculature of pelvic diaphragm
    1. The pelvic diaphragm recieives arterial supply from the internal iliac. In particular, the inferior vesical arteries, the middle rectal arteries, the internal pudendal arteries, and the inferior rectal arteries all supply the pelvic diaphragm. Similarly, veins if the same name provide venus drainage.
  • Innervation of pelvic diaphragm
    1. The levator ani is innervated by the nerve to levator ani derived from S3-4. Additionally, the perineal surface of the levator ani receives innervation from inferior rectal branches of the pudendal nerve.
    2. The ischiococcygeus is supplied by the nerve to coccygeus derived from S4-5.
  • Lymphatic drainage of pelvic diaphragm
    1. Lymphatic drainage of pelvic diaphragm follows branches of the interanl iliac artery to internal iliac nodes, then to upper lumbar nodes, lumbar lymph ducts, and the cysterna chyli. Other drainages include the sacral nodes and the common iliac nodes.
    2. Lymphatic drainage from inferior surfaces may be to the superficial inguinal lymph nodes.

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Written Examination Part IV. (36 pts) - Essay: Abdomen, Pelvis, and Perneum (September 21, 2006)

Note: This is an outline of topics to be covered. It is not the "answer key." It is an answer guide.

Ischiorectal Fossa

Discuss the boundaries and contents of the ischiorectal fossa, fascial specializations, vascularization, innervation, lymphatic drainage, the relationship of the ischiorectal fossa to the superficial and deep pouches, and provide an explanation of your observation that urine does not accumulate in the superficial pouch. (12 pts)
  • General
    • Wedge shaped area located between the ischial tuberosites and the anorectal canal and consisting of a posterior recess and an anterior superior recess.
  • Boundaries of Anterior Superior Recess
    • Superior - inferior fascia of the pelvic diaphragm, most lateral and superior is arcus tendineous
    • Inferior - superior fascia of the urogenital diaphragm
    • Anterior - fusion of superior fascia urogenital diaphragm (transverse perineal ligament) with inferior fascia of pelvic diaphragm at the pubic bone
    • Posterior - open into the posterior recess of the ischiorectal fossa
    • Lateral - inferior - conjoint ramus, intermediate - oburtator internus muscle
    • Medial - fusion of the inferior fascia of the pelvic diaphragm with superior fascia urogenital diaphragm at urogenital hiatus
  • Boundaries of Posterior Recess
    • Superior - inferior fascia of the pelvic diaphragm
    • Inferior - medial: perianal skin, lateral: gluteus maximus
    • Anterior - superior to posterior free edge urogenital diaphragm: anterior superior recess of the ischiorectal fossa, inferior to posterior free edge of urogenital diaphragm: superficial perineal fascia (Dartos)
    • Posterior - gluteus maximus
    • Lateral - gluteus maximus
    • Medial - anal canal
  • Fascial specializations
    • Arcus tendineus - thickening of obturator internus fascia, faces pelvic cavity on superior aspect and ischiorectal fossa on inferior aspect
    • Pudendal canal - thickened covering of obturator internus fascia over falciform edge along medial ischial tuberosity forms osseofibrous pudendal canal from lesser sciatic foramen to the posterior free edge of the urogenital diaphragm at the conjoint ramus
  • Contents and relationships
    • Loose areolar fat - accomodate distention
    • Anal canal
    • Pudendal nerve and branches - inferior rectal, perineal, posterior scrotal, dorsal nerve
    • Internal pudendal artery and branches - inferior rectal, perineal, posterior scrotal, dorsal artery, deep artery, artery to the bulb
  • What fascial barriers prevent spread of infection into the superficial pouch
    • Infection does not spread from the ischiorectal fossa into the superficial pouch because Scarpa's fascia attaches to the posterior free edge of the UG diaphragm. This attachment provides part of the anterior border of the ischiorectal fossa at levels inferior to the posterior free edge of the urogenital diaphragm.
  • What fascial barriers prevent spread of infection into the deep pouch
    • Infection does not spread from the ischiorectal fossa into the deep pouch because the superior fascia of the urogenital diaphragm provides a fascial barrier between the anterior superior recess of the ischiorectal fossa and the deep pouch.
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Left Kidney

Discuss the structure, innervation, vasculature, lymphatics, and releationships of the left kidney. (12 pts)
  • Structure
    • medial and lateral margins
    • hilum and renal sinus
    • fibrous capsule
    • cortex and medulla
    • pyramids and renal papilla
    • major and minor calyx
    • renal pelvis
    • extends through hilum to become ureter
  • Position
    • paravertebral gutters
    • 11th thoracic to 3rd lumbar vertebra
  • Relations to peritoneum and fascia
    • perirenal fat - into renal sinus
    • renal fascia - condensation of ECT, open inferiorly (support and spread of infection)
    • pararenal fat - outside renal fascia, envelopes suprarenal gland and kidney
  • Relations to surrounding viscera (left kidney)
    • superior - suprarenal gland
    • inferior - false pelvis
    • posterior - diaphragm, lumbocosto trigone, 11-12 ribs, quadratus lumborum, psoas major
    • posteromedial - medial and lateral arcuate ligaments, subcostal nerve, iliocostal nerve
    • anteromedial - aorta
    • anterior - suprarenal g., omental bursa, stomach and leinorenal lig., spleen, tail of pancreas, left colic flexure, intestine, descending colon
  • Relations at the hilum
    • anterior to posterior - renal vein, renal artery, renal pelvis
  • Sensory and motor innervation
    • preganglionic sympathetics - imlcc of T10-12, synapse in aorticorenal g.
    • postganglionic sympathetics - renal plexus
    • sensory - T10 - L1, follow renal plexus, referred pain
  • vascular supply
    • left renal vein - crosses aorta in "nutcracker", anterior to renal artery,
    • left renal artery at level of L3,
  • lymphatic drainage
    • lumbar nodes
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Uterus, Uterine Tubes, and Ovary

Indicate your understanding of the uterus, uterine tubes, and ovary as to structure, orientation, relationships (anterior, posterior, superior, inferior, medial, lateral), support(s), and peritoneal associations, innervation (e.g., preganglionic, postganglionic, afferents, pawtways), vasculature, and lymphatics. (12 pts)
  • Uterus
    • Structure
      • Pear shaped hollow organ - 8cm long, 5cm wide
      • myometrium and endometrium
      • cervix, body, fundus
      • external os, cerivical canal, internal os, uterine cavity
    • Orientation
      • anteflexed and anteverted (lengthens posterior fornix vagina)
    • Support
      • intraperitoneal organ
      • Broad lig. - visceral lig (peritoneum)
        • lateral uterus to parietal peritoneum of lateral pelvic wall
      • fibrous ligs derived from endopelvic fascia
        • utereosacral, pubouteral, and lateral cervical (Cardinal) ligs.
      • round lig to lateral anterior pelvic brim - anterior lamina broad lig.
      • ovarian lig to posterior abdominal wall via suspensory lig. ovary
    • Relationships
      • anterior: bladder, vesicouterine pouch
      • posterior: rectum, rectouterine pouch
      • superior: false pelvis, abdominal cavity
      • inferior: vagina, posterior fornix, rectouterine pouch
      • lateral: broad lig, pelvic wall, ovary, uterine tube
    • vasculature and lymphatics,
      • uterine a. at the cervix and ovarian a. at the fundus
        • ovarian v. to ivc on right and left renal v. on left
        • uterine venous complex into internal iliac vv.
      • fundus drains lymph to upper lumbar nodes along ovarian vessels
      • superior body near round ligament drains lymph to superficial inguinal nodes
      • cervix drains lymph toward internal iliac nodes
    • innervation
      • sympathetic by way of inferior hypogastric plexus to uterovaginal plexus along uterine a.
        • preganglionic in IMLCC lower thoracic and upper lumbar
        • postganglionic in microscopic ganglia of aortic and hypogastric plexuses
      • parasympathetic: unknown if present
      • sensory pain follow sympathetic pathways (eg. hypogastric nerves)
  • Uterine Tube
    • Structure
      • shaped as a salpinx and about 10 cm long
      • connects uterine cavity to the peritoneal cavity
      • isthmus, ampulla, infundibulum, fimbriae
    • Orientation
      • courses laterally from fundus of uterus toward pelvic wall
      • intraperitoneal in superior free edge of broad lig.
      • cradles ovary as a posterior relation
    • Support
      • mesosalpinx - visceral lig (peritoneum) part of broad lig.
        • continuous with mesovarium
      • ovarian lig to posterior abdominal wall via suspensory lig. ovary
    • Relations
      • anterior: bladder, vesicouterine pouch
      • posterior: broad lig., rectum, rectouterine pouch, ovary
      • superior: false pelvis, abdominal cavity
      • inferior: broad lig., rectouterine pouch
      • lateral: broad lig, pelvic wall, ovary, ovarian fossa, uterine tube
      • medial: fundus and body of uterus
    • vasculature and lymphatics,
      • tubal a., uterine a. at the cervix and ovarian a. at the fundus
        • uterine venous complex to internal iliac vv
      • drains lymph to upper lumbar nodes along ovarian vessels
      • drains lymph to superficial inguinal nodes
      • drains lymph toward internal iliac nodes
    • innervation
      • sympathetic by way of inferior hypogastric plexus to uterovaginal plexus along uterine a.
        • preganglionic in IMLCC lower thoracic and upper lumbar
        • postganglionic in microscopic ganglia of aortic and hypogastric plexuses
      • sympathetic by way of ovarian plexus
      • parasympathetic: unknown if present
      • sensory pain follow sympathetic pathways
  • Ovary
    • structure and support
      • The ovary is roughly cylindrical about 3 cm long and 1 cm in diameter. The visceral peritoneum covering the ovary gives way to a specialized germinal epithelial cell layer. The egg is able to penetrate this layer and enter the peritoneal cavity.
      • The ovary is suspended from the posterior lamina of the broad ligament by the mesovarium -- a peritoneal ligament. Supporting the superior pole of the ovary to the pelvic brim is the suspensory ligament of the ovary. Supporting the inferior pole of the ovary to the lateral uterus is the ovarian ligament.
    • relationships
      • superior to the ovary is the pelvic brim and suspensory ligament
      • inferior to the ovary is the uterine wall and the ovarian ligament
      • anterior to the ovary is the broad ligament, uterine tube, and fimbria of uterine tube
      • posterior to the ovary is the rectum and pelvic floor
      • medial to the ovary is the pararectal fossa, rectouterine pouch, fundus of the uterus
      • lateral to the ovary is the ovarian fossa (internal iliac a. and ureter), psoas major muscle, and obturator n.
    • innervation (motor and sensory)
      • Parasympathetic preganglionic cell bodies are located in the central gray of the spinal cord (IMLCC) at levels S2-4. Preganglionic fibers enter the inferior hypogastric plexus by way of the pelvic splanchnic nerves. The inferior hypogastric plexus contributes a uterine plexus and then to the ovarian plexus. Postganglionic parasympathetic cell bodies are located in intrinsic ganglia of the ovary. The above pathway assumes that the uterovaginal plexus reaches the ovary. This is not known for certain. Parasympathetic pregangionic contributions from the vagus n. may also follow the ovarian plexus.
      • Sympathetic preganglionic cell bodies are located in the interomedial lateral cell column at cord levels T10 (and perhaps T11-12). Preganglionic fibers follow the lesser and least splanchnic nerves to aortic ganglia near (and including) the superior mesenteric ganglion and the aorticorenal ganglion. Postganglionic fibers from these ganglia enter the aortic plexus and extend along the ovarian artery as the ovarian plexus. Visceral afferent pathways follow the sympathetic pathways up to the T10 spinal level. Additional visceral pathways follow parasympathetic pathways back to the S3-4 spinal levels.
    • blood supply and lymphatics
      • The arterial supply is mostly from the ovarian arteries. These are paired arteries arising from the anterolateral surface of the aorta near the level of the third lumbar vertebra. The ovarian veins arise from the IVC on the right and the left renal vein on the left. Additional blood supply is by ascending branches of the uterine vessels (ovarian br.) that anastomose with the ovarian vascular supply. Lymph drainage is primarily along the embryological decent of the ovary. This includes upper lumbar nodes in the vicinity of the renal arteries. Much of the vascular supply reaches the ovary through the suspensory ligament.

  • Prolaps of Uterus
    • Weakening of the ligamentus support of the uterus leads to prolapse
      • most noteably, the lateral cervical ligs and important
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Topic revision: r1 - 19 Sep 2012, UnknownUser
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