PELVIS AND PERINEUM VIVAS
2010-1, 2007-2
Photo: FEMALE pelvis (pg 274?)
This is a midline sagittal section of a pelvis. Name the major anatomical structures
Major: Pubic symphysis (19), Bladder (29), Vagina (33), Uterus (32), Rectum (22), Sacrum,
Cervix (3), External anal sphincter.
Minor: Ovary (?), Tube (?), suspensory ligament (difficult), L5/S1 disc, Sigmoid (27), Ureter (difficult)
(31)
Describe the boundaries and relations of the Pouch of Douglas
- “Recto-uterine pouch”
- Inferior most extension of the peritoneal cavity, between anterior rectum and posterior uterus
- Close to cervix and posterior fornix of vagina
- Open above to peritoneum
Note: Free fluid can also accumulate in the vesicouterine pouch
2009-2
Discussion: Anatomy of male urethra
Describe the parts of the male urethra and the course of each
Part
Intramural
(preprostatic)
Prostatic
urethra
Intermediate
(membranous)
Spongy urethra
Location/Disposition
Extends almost vertically through neck of
bladder
Through anterior prostate, forming a gentle,
anteriorly concave curve; is bounded
anteriorly by a vertical trough-like part
(rhabdosphincter) of external urethral
sphincter
Passes through deep perineal pouch,
surrounded by circular fibers of external
urethral sphincter; penetrates perineal
membrane
Courses through corpus spongiosum; initial
widening occurs in bulb of penis; widens
again distally as navicular fossa (in glans
penis)
Features
Internal urethral sphincter; diameter and length vary,
depending on whether bladder is filling or emptying
Widest and most dilatable part; features urethral crest
with seminal colliculus, flanked by prostatic sinuses
into which prostatic ducts open; ejaculatory ducts open
onto colliculus, hence urinary and reproductive tracts
merge in this part
Narrowest and least distensible part (except for
external urethral orifice)
Longest and most mobile part; bulbourethral glands
open into bulbous part; distally, urethral glands open
into small urethral lacunae entering lumen of this part
Where is it narrowest?
Membranous part and external urethral orifice
In a case of rupture of the spongy urethra, where does urine extravasate?
- Rupture commonly at the bulb (e.g. a straddle injury, less commonly IDC insertion)
- Around the penis, scrotum and anterior abdominal wall (superficial peroneal pouch)
- Not into the thigh or anal triangle due to facial layers
2007-1
Abdominal Xray - additional question
What is the lymphatic drainage of male genitalia
- Testicles: run back along testicular artery to paraaortic nodes, lying along L2 level
- Scrotal and penile skin: to inguinal nodes
2008-2
Photo pelvis – additional question
Describe the innervation of the bladder
- Presynaptic sympathetic fibers (T11-L2/3) via hypogastric plexus (contracts internal urethral
sphincter, important in prevention of retrograde reflux of semen in ejaculation)
- Presynaptic parasympathetic fibers (Motor to detrusor and inhibitory to internal urethral sphincter)
(S2-4) via Splanchnic nerve and inferior hypogastric nerve –> bladder emptying
- Cortical suppression of this (w/ toilet training)
- These synapse with post synaptic neurons on or near bladder wall
- Inferior to pelvic line (reflex and pain) the visceral afferents follow parasympathetic fibers
retrograde to S2-4 spinal ganglia
- Superior to pelvic line (pain) - follow sympathetic fibers retrograde to T11-L2/3
- Somatic innervation to external urethral sphincter, urethra via pudendal nerve (S2-4)
Identify any nerves that innervate the bladder
Superior hypogastric plexus (37), Inferior hypogastric plexus and Splanchnic nerve (21), left and right
hypogastric nerve (16)