Lecture 24 - Neurovasculature of the Pelvic Region Flashcards
What is the primary blood supply to the pelvic region?
Internal iliac artery
Where does the internal iliac artery originate?
From the common iliac artery
Where does the common iliac artery run?
Infero-laterally
Where does the common iliac artery bifurcate?
At the sacroiliac joint
What does the common iliac split into?
- External iliac a.
- Internal iliac a.
What are the two divisions of the branches of the internal iliac artery?
- Anterior
- Posterior
Where do the branches of the anterior division go?
- Pelvic viscera
- Perineum
- Gluteal region
Where do the branches of the posterior division go?
- Lower abdominal
- Pelvic walls
- Gluteal region
What are the anterior branches of the internal iliac artery?
- Obturator a.
- Inferior gluteal a.
- Inferior vesical a.
- Middle rectal a.
- Internal pudendal a.
- Superior vesical a.
Where does the obturator artery go?
Through obturator foramen, to medial thigh
Where does the inferior gluteal artery go?
Through greater sciatic foramen, to gluteal region
Where does the inferior vesical artery go?
To bladder + seminal vesicle (AMAB)
Where does the middle rectal artery go?
To rectum
Where does the internal pudendal artery go?
To external genitalia and perineum
Where does the superior vesicle artery go?
To distal ureter, bladder + seminal vesicle, vas deferens (AMAB)
What are the posterior branches of the internal iliac artery?
- Iliolumbar a.
- Lateral sacral a.
- Superior gluteal a.
Where does the iliolumbar artery go?
To posterior abdominal wall muscles and iliacus
Where does the lateral sacral artery go?
To sacrum and pelvic wall
Where does the superior gluteal artery go?
Through greater sciatic foramen to gluteal region
Which division is the same in both AMAB and AFAB?
Posterior division
Which arteries of the anterior division are similar amongst AMAB and AFAB?
- Obturator a.
- Inferior gluteal a.
- Internal pudendal a.
- Superior vesical a. + umbilical a.
Which arteries of the anterior division are different in the AFAB?
- Middle rectal a.
- Uterine a.
- Vaginal a.
Where does the middle rectal artery go in an AFAB?
To rectum + branch to vagina (AFAB)
Where does the uterine artery go?
To uterus
What does the uterine artery pass over?
Over the ureter
Where does the vaginal artery go?
To the vagina
In an AFAB, what is equivalent to the inferior vesicle artery in an AMAB?
The uterine and vaginal a.
What is the blood supply to the uterus, uterine tube and ovary?
- Ovarian a.
- Uterine a.
- Vaginal a.
What supplies the lower parts of the vagina?
Vaginal a.
What supplies the cervix and upper parts of the vagina?
Descending branch of the uterine a.
What supplies the uterus?
Ascending branch of the uterine a.
What supplies the uterine tube and ovary?
Anastomosis between the ovarian a. and the ascending branch of the uterine a.
Where does the internal pudendal artery leave?
The pelvic cavity through the greater sciatic foramen
Where does the internal pudendal artery pass after exiting the pelvic cavity?
Lateral to the ischial spine
Where does the inferior pudendal artery enter next?
Re-enters the pelvic cavity through the lesser sciatic foramen
Where does the inferior pudendal artery pass through after entering the pelvic cavity?
The pudendal canal
Where does the inferior pudendal artery run after passing through the pudendal canal?
- Along the inferior border of obturator internus
- Medial to ischial tuberosity
- Superficial to levator ani
- Enters perineum
What is the blood supply to the rectum and anal canal?
- Superior rectal a.
- Middle rectal a.
- Inferior rectal a.
What do the 3 rectal arteries form?
A long anastomosis along the rectum
Where does the superior rectal artery come from?
Terminal branch of the inferior mesenteric a.
Where does the middle rectal artery come from?
Comes straight off the anterior division
Where does the inferior rectal artery come from?
Internal pudendal a.
What is the blood supply to the perineum?
Via branches of the internal pudendal a./v.
What are the branches of the internal pudendal a./v.?
- Inferior rectal a./v.
- Perineal a./v.
What do the perineal arteries supply in an AMAB?
- Erectile tissues and covering muscles
- Scrotum
What do the perineal arteries supply in an AFAB?
- Labia
- Bulb glands
What is the pudendal nerve?
Spinal nerve from the sacral plexus (S2-S4)
What modality does the pudendal nerve give?
Somatic innervation
What type of innervation does the pudendal nerve give?
Mixed sensory and motor
Where does the motor innervation of the pudendal nerve go to?
- Bulbospongiosus
- Ischiocavernosus
- External anal and urethral sphincters
- Levator ani
- Transverse perineal m.
Where does the sensory innervation of the pudendal nerve go to?
- Genitalia
- Anus
Where does the pudendal nerve exit?
The pelvic cavity via the greater sciatic foramen
Where does the pudendal nerve travel after exiting the pelvic cavity?
Hooks posteriorly around the ischial spine/sacrospinous ligament
Where does the pudendal nerve enter next?
Re-enters the pelvis via the lesser sciatic foramen
What canal does the pudendal nerve travel through?
Pudendal canal
Does the pudendal nerve follow the same path in AMAB and AFAB?
Yes
Where does the pudendal nerve go up to?
The inferior rectal n. (to anus and external anal sphincter)
What is the treatment for a pudendal nerve block?
Local anesthesia is administered near the attachment of the sacrospinous ligament/ischial spine
What is the sympathetic innervation of the pelvic viscera?
Lumbar splanchnic n. to superior hypogastric plexus via hypogastric nerves
Where are fibers also received from?
Sacral splanchnic n. on the way to inferior hypogastric plexus
What is the parasympathetic innervation of the pelvic viscera?
Pelvic splanchnic n. arising from sacral segments S2-S4
What does the pelvic splanchnic join?
Sympathetic fibers in inferior hypogastric plexus
What is the inferior hypogastric plexus?
Main ANS plexus of pelvic viscera
What does the inferior hypogastric plexus receive?
- Lumbar and sacral splanchnic n. (SNS)
- Pelvic splanchnic n. (PSNS)
Where is the inferior hypogastric plexus located?
Bilaterally around the rectum, inferior bladder, prostate/seminal vesicles (AMAB), and vagina (AFAB)
What is the function of the autonomic innervation of the pelvic splanchnic n. (S2-S4)?
- Increase GIT motility
- Relaxation of internal sphincters
- Contraction of detrusor muscle
- Relaxation of uterine musculature
- Vasodilation in erectile tissues
What is the function of the autonomic innervation of L1-L2?
- Decrease GIT motility
- Contraction of internal sphincters
- Relaxation of detrusor muscle
- Contraction of uterine musculature
- Contraction of smooth muscles of the vas deferens, seminal vesicle, and prostate