Posted by lae2 on October 13, 2021 at 17:50:31:
Discuss the structure, relationships, innervation, vasculature, lymphatics, relationships and clinical significance of the bladder, highlighting differences between males and females.
Discuss the structure, relationships, innervation, vasculature, lymphatics, and clinical significance of the rectum.
Cirrhosis of the liver causes portal hypertension. Discuss the anatomy of the anal canal along with the anatomical basis for internal hemorrhoids.
True False Questions
The median umbilical ligament arises from the apex of the bladder.
The neck of the bladder in the female sits on the superior surface of the urogenital diaphragm in a region known as the urogenital hiatus.
The pubovesical ligament can be used to elevate the floor of the pelvic diaphragm by suturing to the pectineal ligament within the retropubic space (treatment for urinary incontinence).
The ureteric orifices are located at the apices of the base of the trigone.
In the male, the inferior apex of the trigone gives rise to the uvula.
The superior vesical arteries supply the anterosuperior region of the bladder and are the final branches of the patent umbilical artery before obliteration into the medial umbilical ligament.
The prostatic and vesical venous plexuses drain into tributaries of the internal iliac veins.
The prostatic venous plexus may spread prostatic cancer to the vertebral canal by way of lateral sacral veins.
The bladder is "allowed" to relax and accumulate urine by way of sympathetic inhibition applied to the parasympathetic innervation of the detrusor muscle.
Parasympathetic innervation of the bladder drives contraction and, thus, voiding and, at the same time, parasympathetic innervation relaxes the internal urethral sphincter to facilitate urine flow.
The peritonealized surface of the bladder conveys nociceptive information along sympathetic pathways toward the lower thoracic and lower lumbar cord levels.
Retroperitoneal regions of the bladder (below the pelvic pain line) convey nociceptive information along parasympathetic pathways (pelvic splanchnic nerves) to the S2-4 cord levels.
A perturbed neck of the bladder may refer pain to the foot.
The rectum and the anal canal as far distal as the pectinate (dentate) line are derivatives of the hindgut.
Three transverse rectal folds, two on the left and one on the right, provide shelves to support fecal contents and, thus, contribute to fecal continence.
The ampulla of the distal rectum ends at the level of the anal aperture of the pelvic diaphragm and forms the anorectal junction.
The anal canal begins at the pelvic diaphragm and proceeds about two centimeters further distally to end at the anus.
A "puborectal sling" is formed by the puborectalis muscle at the proximal anal canal and is a functional sphincter that closes the canal and, thus, contributes to fecal continence.
The anterior wall of the distal rectum is adjacent to the peripheral zone of the prostate and, thus, the posterior prostate can be palpated by a digital rectal examination.
Lymphatic drainage from the proximal rectum is toward inferior mesenteric nodes (inferior mesenteric vessels).
Lymphatic drainage from the middle rectum is toward internal iliac nodes (middle rectal vessels).
Lymphatic drainage from the distal rectum and proximal anal canal (proximal to dentate line) is to internal iliac nodes (internal pudendal vessels).
Lymphatic drainage from the anal canal distal to pectinate line is toward superficial inguinal nodes (external pudendal vessels).
Internal hemorrhoids occur proximal to the dentate line and reflect a portacaval shunt between the superior rectal vein and the middle/inferior rectal veins.
The internal anal sphincter is contracted by sympathetic tone, whereas the external anal sphincter is contracted by somatic tone (inferior rectal nerves from pudendal nerve).
Peristalsis against a filled rectal ampulla causes relaxation of the internal anal sphincter and thus, the somatic innervation to the external anal sphincter, levator ani, and puborectalis is primary in assuring continued fecal continence.
A midline episiotomy may infringe upon the external anal sphincter and, thus, carries the risk of fecal incontinence.
A mediolateral episiotomy may infringe upon the muscles or nerves of the deep pouch and, thus, carries the risk of urinary incontinence.
The internal rectal venous plexus is proximal to the dentate line at the level of the anal columns and is the source of internal hemorrhoids.
Sympathetic tone maintains contraction of the internal anal sphincter during filling of the rectal ampulla, whereas parasympathetic tone relaxes the internal anal sphincter during rectal peristalsis.
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