Pelvis Day 2 Flashcards
pathway of the ureter
It begins retroperitoneal, then it is crossed by either the ductus deferens or uterine artery. It passes over the pelvic brim to run alongside the lateral walls of the pelvis. It then turns anteromedially to enter the bladder.
What prevents retrograde flow of urine from the bladder to the ureter?
There is a one way flap in the bladder and the internal pressure of the bladder prevents this back flow.
Which part of the bladder is covered by peritoneum?
The roof of it.
Explain how the bladder grows when it is filling.
The bladder is actually sub peritoneal, but as it fills and distends it grows into the extraperitoneal tissue between the anterior abdominal wall and the peritoneum. At this point it is in the greater pelvis.
What attache the apex of the bladder to the anterior abdominal wall?
The median umbilical ligament which was the urachus in the embryo.
Where does the rectum begin?
Anterior to S3 at the rectosigmoid junction
Where does the rectum end?
At the anorectal junction as the rectal ampulla. This occurs around the tip of the coccyx.
What is the first flexure of the rectum?
The sacral flexure. It is in an anterior to posterior plane.
What creates the perineal flexure of the rectum and why is this flexure important?
The coccygeus muscle creates this and it’s important for maintaining continence.
Where does the anal canal begin?
The anal canal begins at the anorectal junction.
Where does the anal canal end?
At the anus.
What is the innervation of the internal anal sphincter?
Innervated by autonomic nerves from the superior rectal plexus.
Describe the effects of sympathetics and parasympathetics on the rectum?
Sympathetic fibers stimulate contraction, parasympathetic fibers inhibit contraction.
Describe the innervation of the external anal sphincter
It is innervated by the inferior rectal branch of the pudendal nerve. It is under somatic motor control!
What junction does the pectinate line represent?
The junction between the superior and inferior anal canal
Vessels above the pectinate line include:
Superior rectal arteries, superior rectal veins, internal iliac lymph nodes, autonomic innervation
Vessels below the pectinate line include:
Inferior rectal arteries, inferior rectal veins, superficial inguinal lymph nodes, somatic innervation via inferior rectal nerve of pudendal nerve.
Describe the pathway for sperm
Testis (seminiferous tubules to rete testis to efferent ductules)–> epididymis–> ductus deferens–> seminal vesicles–>ejaculatory duct–>prostrate–>urethra
Describe the pathway of the ductus deferens
It ascends through the inguinal canal as part of the spermatic cord. Then it runs subperitoneally over the external iliac arteries and lateral wall o the pelvis. It then crosses superior to the ureter, and posterior to the bladder, it first lies superior to the seminal vesicle, then descends medial to the ureter and seminal vesicle. It enlarges to form the ampulla of ductus deferent before its termination in the ejaculatory duct.
Relationships surrounding the seminal vesicles
Lateral to ampullae of ductus deferens, superior to the prostrate, and inferior to the ureters
Relationships surrounding the prostate
lies between the neck of the bladder, the perineal membrane and posterior to the pubic symphysis, posterior surface related to the rectum
What separates the two lateral lobes of the prostate
prostatic urethra
What lobe of the prostate is palpable via the rectum
The posterior lobe. Also likely to become cancerous
What is the clinical significance of the supravesical fossa?
When the bladder fills, it rises into this area (in males) therefore a catheter can be inserted into the bladder in this area without penetrating the peritoneal cavity.
