8.3 Vessels, nerves & lymphatics of the Pelvis Flashcards
What is the main blood supply for the pelvis?
Internal iliac artery
What are some smaller arteries that supply the pelvis?
Ovarian arteries, testicular arteries, superior rectal artery, medical sacral artery
What level does the abdominal aorta divide into the common iliac branches?
L4-L5
What are the two branches of the Internal iliac artery?
Posterior and Anterior branch
Where does the posterior internal iliac artery branch to?
Branches to the body wall
Where does the anterior internal iliac artery branch to?
Branches to the body wall and to the viscera
What are the posterior internal iliac artery branches?
Iliolumbar, Lateral sacral and Superior gluteal
What are the anterior internal iliac artery branches?
Obturator, Inferior gluteal and Internal pudendal
What are the visceral branches of the Internal iliac artery?
Superior vesical (to bladder), Middle rectal, Uterine and Vaginal arteries
What do the Uterine and Vagina arteries have to do with each other?
They anastomoses together
How does the superior mesenteric vein drain?
It drains to the portal system via the inferior mesenteric vein
Where does the internal iliac vein drain to?
It drains into the IVC
Name the large visceral venous plexuses
Vesical, Prostatic, Uterovaginal, Rectal
Do the venous plexuses of the pelvis have valves?
No, meaning blood can flow either direction
What is different with the Prostatic venous plexus?
Normally drains to the IVC, has a retrograde drainage of the prostate via valveless veins to the vertebral canal via anterior sacral veins
What can spread through the path venous blood takes through the body from the prostatic venous plexus?
Cancer can spread through the vertebral canal after moving from the prostate
What veins are involved with a porto-systemic anastomoses in the pelvis?
Super rectal vein (portal) with middle and inferior rectal veins (systemic)
What might happen with an elevation in portal venous pressure?
May result in distension of thin walled communicating veins at sites of portal systemic anastomoses
What direction does lymph flow?
Superficial to Deep
Where does lymph from the pelvic viscera drain?
Drains to deep lymph nodes
Where does lymph from the skin of the perineum drain to?
Drains to inguinal nodes then to superficial lymph nodes
What 2 places do lymph from pelvic viscera drain to?
Nodes along iliac vessels and para-aortic nodes
Where does lymph from the testes drain to?
It drains to para aortic nodes on the posterior abdominal wall
Where does lymph from the scrotum drain to?
It drains to inguinal nodes
What is a problem with the lymph in the pelvis?
That they are situated deeply and cant be palpable. One man only learn about cancer when it reaches the clavicular nodes
What supplies muscles of the pelvis?
Sacral plexus (S2-4)
What are the main branches of the sacral plexus?
Obturator and Pudendal nerves
What does the Pudendal nerve innervate?
The Perineum and external genitalia
What is unusual about the positioning of the Pudendal nerve?
It supplies all its branches from below to allow for no compression
What are 3 nerve areas of visceral nerves in the Pelvis?
Superior hypogastric plexus- Sympathetic (T11-L1), Inferior hypogastric plexus- Mixed sym/para, Pelvic splanchnic nerves (S2-4)
What supplies the rectum and anal canal?
Above the pectineal line the supply is from the superior rectal artery. Below the pectineal line the supply is from the inferior and middles rectal arteries
Describe the micturition reflex
Involves parasympathetic S2-4 to contract the detrusor muscle, relaxation of involuntary internal urethral sphincter by sympathetics T12-L1, and relaxation of voluntary external urethral sphincter via the pudendal nerve
Describe the defaecation process
Faeces collect in lower anal canal, defaecation is inhibited by contraction of internal and external sphincter, stretch of the canal stimulates PNS to inhibit SNS to relax internal anal sphincter and Pudendal nerve voluntarily relaxes external sphincters
Describe the erection process
Erection is due to parasympathetic stimulation, there is compression of veins and restriction of venous drainage
What is ejaculation mediated by?
The sympathetic nervous system T12-L1
What does pain travel with when it is above the pelvic line?
Visceral pain passing with sympathetics
What does pain travel with when it is below the pelvic line?
Pain travels with parasympathetics
