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The Structural Basis of Medical Practice (SBMP) - Human Gross Anatomy, Radiology, and Embryology
Answer Guide for Abdomen, Pelvis, and Perineum: Written Examination Part III (58 pts) - 1998
The College of Medicine at The Pennsylvania State University
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Note: This guide indicates key points to address in answering the question. This is not the "answer."
Part III. Answer in the space provided. (58
pts)
1. A 57-year old professor is taken to the emergency room with sudden and
severe pain in the abdomen. He has a history of stomach ulcers.
Further tests and examinations reveal a perforation of the posterior wall
of the stomach, with gastric contents spilling into the lesser sac. Define
the boundaries (including spaces and/or recesses of the lesser sac (omental
bursa)). Explain why damage to the stomach would produce sharp pains
in the abdomen. Discuss the pathway of materials that appear in the
greater sac, and provide infromation about the location of these fluids/food
contents with respect to body position. (10 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 of 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
-
Why sharp pain?
-
Irritation of the parietal peritoneum of the posterior wall activates somatic
afferent nerves.
-
Pathway of Materials?
-
Person rolls to the left - 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
2. The relationship of the ovary to reproduction demands a through
knowledge of this structure. Discuss the anatomy of the ovary, and
include a) structure and support, b) relationships, c) innervation (motor
and sensory), and d) blood supply and lymphatics. (10 pts)
-
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 penetrates this layer to 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.
-
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.
-
Parasympathetic pregangionic contributions from the vagus n. may also follow
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.
-
Paired arteries arise 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.
Anastomotic branches enter the mesovarium
-
Lymph drainage is primarily along the embryological decent of the ovary.
-
Follows ovarian vessels toward upper lumbar nodes in the vicinity of the
renal arteries.
-
Follows ovarian and round ligaments to the mons pubis and superficial inguinal
nodes
-
Follows the uterine artery toward internal iliac nodes.
3. While a riding a bicycle, a 14-year old boy skids on a rain-soaked
street, lacerates the perineal membrane (inferior fascia of the urogenital
diaphragm) and damages the urethra. In the emergency room the patient
is found to have extravasation of urine. Discuss the boundaries and
fascial relationships that define the accumulation of urine. In your
discussion be specific as to terminology of fascial planes and elaborations.
(8 pts.)
-
General Comment
-
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 prevents urine from entering
the ischiorectal fossa. The accumulation of urine will be restricted
by the boundaries of Scarpa's (membranous) fascia proper and the derivatives
of Scarpa's 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
-
medial: 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 - between superficial perineal fascia (derivative of
Scarpa's fascia) and perineal membrane (deep fascia)
-
superior: perineal membrane
-
inferior: superficial perineal fascia
-
anterior: open into scrotum
-
posterior: posterior free edge of urogenital diaphragm
-
lateral: conjoint rami
-
medial: not restricted
4. Discuss the course and branches of the internal pudendal artery
in the pelvis, gluteal region, ischiorectal fossa, 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. (8 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
-
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
-
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
5. Discuss the structure, relationship(s) to the peritoneum and surrounding
viscera and at the hilum, sensory and motor innervation, vascular supply,
and lymphatic drainage 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
-
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
6. Indicate your understanding of the anatomy of the diaphragm and
include discussion of muscles, ligaments, site(s) of weakness and attachment,
the location and structures coursing between the thorax and abdomen, as
well as the innervation, vascular supply, and lymphatics of the diaphragm.
(10 pts)
-
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
-
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
-
vertebral level L1/L2
-
Apertures
-
aperture for the IVC (inferior vena cava) at vertebral level T8
-
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
-
aperture for the aorta (aortal hiatus) at vertebral level T12
-
Pathways of structures coursing between thorax and abdomen
-
IVC enters abdomen through hiatus for IVC
-
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
-
posterior to the lateral arcuate ligament
-
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
-
superior diaphragm - left side
-
inferior - aorta, stomach, and spleen
-
posterior diaphragm - right side
-
anterior - left kidney and suprarenal g. and the liver
-
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
-
Blood supply
-
anterior peripheral by musculocutaneous a. v. and anterior intercostal
a. v.
-
posterior peripheral by posterior intercostal a. v.
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pericardiacophrenic vessels
-
superior phrenic a. v.
-
central tendon by inferior phrenic a. v. and
-
right vein drains into IVC whereas the left drains into the left renal
vein
-
Innervation
-
peripheral sensory by intercostal n.
-
central tendon motor and sensory by phrenic n.
-
Lymphatic Drainage (note: the lumbar nodes were most important to mention)
-
parasternal nodes
-
posterior mediastinal nodes
-
lumbar nodes
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The Structural Basis of Medical Practice - Human Gross Anatomy
The College of Medicine
of the The Pennsylvania State University
Email: lae2@psu.edu
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