Pelvic Neurovasculature Flashcards
Describe abdominal aorta - what branches supply pelvic region
2 common iliac arteries
Transition to 2 lower limbs
Bypasses rectum
L4
Describe common iliac artery
4 cm long
Originate from aortic bifurcation at L4
Runs inferomedially, along medial aspect of psoas major
Ends over sacroiliac joint
What does common iliac artery give
Internal iliac artery = into lesser true pelvis, reaches pelvis and gives many brnaches, for pelvic cavity
External iliac artery = lower limb, outside = passes under inguinal lig and then becomes femoral
Describe internal iliac artery
1 on each side of pelvis
From common iliac artery
Courses inferiorly over pelvic inlet
Where does internal iliac artery divide
At level of greater sciatic foramen = divides into anterior trunk and posterior trunk
What does internal iliac artery divide into
Anterior trunk and posterior trunk
Describe anterior trunk of internal iliac
Aims anterior
To all pelvic viscera
Perinuem - erectile tissue
Gluteal region
Describe posterior trunk of internal iliac
Not for viscera
Lower abd wall
Posterior pelvic wall
Gluteal region - muscle mainly
What branches does posterior trunk give
Iliolumbar artery
Lateral sacral arteries
Superior gluteal Artery
Describe iliolumbar artery
Acends laterllay out of pelvic inlet
Will reach lumbar region and iliac bone and region
What branches does iliolumbar artery give
Lumbar branches = to post abd wall, psoas, quadratus
Iliac branches to iliac fosssa for iliacus muscle and iliac bone, colon sits here
Describe lateral sacral arteries
Course medically and inferiorly to posterior pelvic wall = skin, dermis, thoracolumbar fascia
Supplies sacrum and skin of sacral region
Feeds sacrum, passes through sacral formamina
describe superior gluteal artery
Largest and terminal branch of posterior trunk, int iliac artery
Leaves pelvis through greater sciatic foramen above piriformis
Supplies muscle and skin of gluteal region, part of lumbar and sacral plexus, between lumbosacral trunk and s1
What does anterior trunk of internal iliac give
- Umbilical artery
- Superior vesical artery
- Inferior vesical
- Vaginal artery
- Uterine artery
- Middle rectal artery
- Obturator artery
- Internal pudendal artery
- Inferior gluteal artery
Describe umbilical artery
1st brnach of anterior trunk
Will give superior vesicle arteries
Rest of vessel is obliterated forming medial umbilical ligament- remnant of fetal circulation
No anatomical variation
Describe medial umbilical ligament
Bit lateral,remnant of obliterated umbilical artery, fibrotic tissue
When umbilical cord cut = segment of tube between bladder and umbilicus = collapse and becomes fibrotic
Recall*median umbilical ligament that suspends bladder
Describe superior vesical artery
Originates from umbilical artery
Supplies superior bladder and distal part of ureter
Little branches, right where obliterated portion starts
Describe anterior trunk amab branches
Inferior vesical artery = supplies bladder, ureter, seminal vesicles and prostate
Under bladder, = prostate, seminal vesicles,
Describe anterior trunk afab branches
Vaginal and uterine -variations
Describe uterine artery
Courses in broad ligament - transverse cervcial ligament - fibrotic thickening protecting uterine and vaginal arteries
Crosses ureter to reach cervix
Supplies = uterus, also contributes to ovary and vagina vasculature
From lateral pelvis to lateral cervix
Describe vaginal artery
Euqavlent of inferior vesicle in amab
Somtimes from uterine artery
Supplies = vagina, bladder and rectum
Describe what afab arteries/veins do
Ovarian connects with uterine connects with vaginal
All interconnected
Veins do the same = big venous system
Anastomotic system
Link to vulvar region
Describe middle rectal artery
Course medially to supply rectum
Anastomoses with superior rectal artery - from inf mesenteric artery and ifnerior rectal artery - from internal pudendal of perinuem
Describe obturator artery
Courses anteriorly along pelvic wall
Leaves pelvic cavity through obturator Foramen, from ant wall
Supplies medial adductor region of thighs
Describe internal pudendal arteyr
Leaves pelvic cavity through greater sciatic foramen inf to piriformis
Loops around ischial spine and sacrospinous ligament
Enters lesser sciatic foramen to reach perineum
Supplies perineum (urogenital and anogenital triangles) and related structures
Describe inferior gluteal artery
Terminal branch of internal iliac
Passes between sacral nerve s2 and s3
Leaves pelvic cavity through greater sciatic foramen ifnerior to pirifomis
How to tell apart inferior gluteal and internal pudendal
Inferior gluteal = post posterior vessel
Compared to internal pudendal -more anterior - close to tip of coccygeus muscle
Describe veins - Gen
Follow course of arteries
Except for umbilical and iliolumbar arteries = no veins
Name all veins
- Superior vesical vein
- Inferior vesical / vaginal vein * Uterine vein
- Middle rectal vein
- Obturator vein
- Internal pudendal vein
- Inferior gluteal vein
Describe drainage of pelvic cavity- Gen
Veins drain into internal iliac vein
Leaves pelvic cavity
Joints external iliac vein
Form common iliac vein
2 iliac vein- one on each side - join to form Ivc
*drains INTO CAVAL system not portal system
Describe drainage of pelvic cavity - plexuses
Venous drainage of Pelvic cavity: interconnected venous plexuses Associated with organs:
Bladder, rectum, prostate, uterus, vagina
All together to form pelvic venous plexus
Describe portosystemic anastomosis- gen
Superior rectal = inf mesenteric vein - portal system (portal)
Middle rectal = internal iliac - systemic (CAVAL)
Inferior rectal = internal pudendal - systemic (CAVAL)
Describe portosystemic anastomosis - specifics issue
If porto caval hypertension
Blood pools, superior rectal cannot drain since drains into portal system
So mid and inf rectal veins drain into ivc, so sup rectal vein no longer capable fo absorbing blood so pools down into mid and inf rectal veins = swollen, hemorrhoids
Describe pelvic congestion syndrome - pcs
Medical condition that causes chronic pelvic pain in afab
Due to reduced venous drainage form left ovarian vein
Could lead to Vulvar varicosities
Network ovarian vessels, Anastomose with uterine and vaginal = veins reach vulva - during cycle = pain, congestion, discomfort
Describe somatic innervation of pelvis
Sacral plexus and perinuem
Describe sacral plexus - somatic innervation
Formed by ant rami of s1-4 (each comes from sacral foramina)+ l4-5 = lumbosacral, joins to form big nerve
Found on anterior surface of priformis
Mostly for lower lim but also for pelvis and perinuem =forms sacral plexus, motor and sensory to lower limb and post thigh
= sciatic nerve, biggest nerve, leaves via greater sciatic formaen under piriformis
Describe perineum - somatic innervation
Pudendal nerve s2,3,4 = motor and sensory
Leaves pelvic cavity through greater sciatic foramen udner piriformis
Pass around sacrospinous ligament and loops over ischial spine
Through lesser sciatic foramen to reach perineum with internal pudendal vessels
Describe pudendal block
Pudendal block: Anesthesia is performed by infiltration near attachment of sacrospinous ligament, ischial spine
Describe superior hypogastric plexus
Same as aortic plexus but below aortic bifurcation
Connected to inferior hypogastric plexus via hypogastric nerv
Below stomach, bifurcation around rectum, extension, hypogastric nerv and will reach inf hypo plexus
Describe visceral innervation - Gen
Plevic extension of superior hypogastric plexus
Carry autonomic innervation - sympathetic and parasympathetic
Enter pelvis via 2 hypogastric nerves, one on each side
Will form inferior hypogastric plexus, around plevic vsicera
*vagus doesn’t supply hindgut, stops 2/3 trasnverse colon
Describe visceral innervation - pathway
Lumbo sacral trunk —>lumbo sacral plexus
Sacral splanchnic = leaves chain, sympathetic,reaches inf hypogastric plexus
Pelvic splanchnic = parasympathetic,leaving sacral nerve
SPLANchNIc NOT JUST PSNS - sns too
Describe visceral innervation sympathetic - paravertebral sympathetic trunk
Inferior end of sympathetic trunk in pelvic cavity Pass anterior to paramedial aspect of sacrum, Join to form one terminal single ganglion (impar)
Describe visceral innervation sympathetic - paravertebral sympathetic trunk DISTRIBUTIONN
Postganglionic fibers reach sacral nerves
Preganglionic fibers reach inferior hypogastric plexus by using a splanchnic nerve
Sympathetic: S = Sacral splanchnic nerves
Describe visceral parasympathetic invvertaion
Originate from S2-S4 anterior rami of sacral nerve
Carry preganglionic parasympathetic fibres to inferior hypogastric plexus
Pelvic splanchnic nerves (S2-S4): P=Parasympathetic
Describe direction of symp/parasymp
Vagus goes down therefore psns (ascending) goes up
And sns goes Down (descending)
Describe psns and action
From pelvic splanchnic
Action:
* Generally vasodilator of vessels
* Stimulate bladder contraction: voiding
* Stimulate erection: Relaxation of branches of deep penile arteries
* Modulate activity of hindgut
Describe sns and action
Enters from hypogastric nerve & sacral splanchnic
Action:
* Innervate blood vessels
* Cause contraction of internal urethral sphincter
* Cause contraction of smooth muscle associated with reproductive
tract, accessory glands
* Peristalsis for moving secretion of epididymis and associated
glands during ejaculation
Describe pathway of parasympathetic
S2,3,4 —> pelvic splanchnic —> Reach inf hypogastric plexus —> Hypogastric nerve —> superior hypogastric plexus —> Aortic plexus —> Inferior mesenteric artery and plexus —> Hindgut
