Transcript Lecture Pelvic Neurovascular 2008

Sacral Plexus & Nerves
ANS
Major arteries
Accessory arteries
Major veins
Accessory veins
Cavity lymphatics
Perineum lymphatics
Gross Anatomy
From School
1. Location: lies ant to& covered with pelvic fascia w/
nerves exiting in greater sciatic foramen
2. Comp: Ventral rami of:
a) lumbosacral trunk –
1. Sciatic n. – largest; major n. of LL
a) comp:
b) exits:
c) splits into:
1. Tibial n. –
2. Common fibular n. –
superficial & deep fibular nerves
2. Pudendal n. –
a) comp:
b) Exits: inf to piriformis m., crosses over
lig, & re-enters in lesser sciatic f. 
c) Enters Pudendal canal – medial border of
 neurovascular bundle
d) Pudendal n. in canal divides into:
1. Inf rectal n. – near entrance of pudendal canal 
a) motor: ext. anal sphincter & levator ani
b) sensory: skin of anal triangle
2. Dorsal n of penis (clitoris) – descends in pudendal canal
& in
F = primary
3. Perineal n. – descends in canal &
& divides into:
a) Deep perineal n. – enters
motor: muscles of deep & sup perineal pouches
sensory: vestibule & inf. vagina
b) Superficial perineal n. –
becomes 
posterior scrotal or labial n. - sensory
3. Other branches of sacral plexus:
Name
Spinal Seg
Function
Sup gluteal
Inf gluteal
N. to obturator internus
N. to quadratus femoris
Post femoral cutaneous n
Perforating cutaneous n.
N. to piriformis
N. to levator ani, coccygeus, ext anal sphincter
1. Sacral paravertebral trunk (2) – ganglia of the
sympathetic trunk in pelvic cavity;
a) courses over ala & descends medial to ant.
sacral foramina
b) Ganglion impar –
2. Sacral prevertebal trunk – carries sympathetic,
parasymp, & visceral afferent fibers for pelvic organs &
3. Superior hypogastric plexus –
distributes sacral prevertebal fibers to 
4. Rt & lt hypogastric nerves – descend into pelvic cavity
and connect with 
5. Rt & Lt inf hypogastric plexus (2) – composed of:
Pelvic splanchnic n. -
6. Subsidiary plexuses – inn by inf. hypogastric plx:
a) Rectal plexus
b) Vesicle plexus
c) Uterovaginal (Prostatic) plexus –
1. Cavernous n. – from prostatic plexus 
erectile tissues of penis
1. Def: major artery of the perineum
2. Origin: bifurcation of common iliac a. @
lumbosacral joint
3. bifurcates at pelvic brim into: ant. and post trunks
a) Anterior trunk – pelvic viscera, perineum, gluteal
region, medial thigh, placenta
b) Posterior trunk - post abdominal & pelvic walls +
gluteal region of hip
4. Posterior Trunk (Prox  dist):
a) iliolumbar a. – ascends above pelvic brim along
lumbosacral trunk:
1. iliac branch – serves iliac fossa
2. lumbar branch – lower post abdominal wall
b) Lateral sacral a (2) – ant. sacral foramina to serve
sacrum & skin
c) Sup. gluteal a. – greater sciatic notch, above piriformis
to serve gluteal region
5. Anterior Trunk (prox  dist):
a) Umbilical a –adjacent to pelvic inlet
ascends in ant. abdominal wall to umbilicus; one
branch:
Superior vesical a.– serves distal ureter, superior surface
of bladder, ductus deferens
b) Obturator a – below margin of pelvic brim, descends
through obturator foramen w/ n. (above) & v. (below);
serves medial thigh compartment
c) Inf. vesical (vaginal) a. – inf. bladder, ureter, seminal
vesicle, & prostate (vagina), part of rectum)
d) Middle rectal a – serves rectum; anastomoses w/:
1. Superior rectal a – from inf. mesenteric
2. Inferior rectal a - from internal pudendal
e) Internal pudendal a. – main artery of perineum
1. greater sciatic foramen - inf to piriformis
2. re-enters in lesser sciatic f. thru pudendal canal
3. Branches of int. pudendal a.:
a) Inf. rectal a. – ischioanal fossa  middle rect. a.
b) Perineal a. – pudendal canal  sup. pouch
w/ branches:
1. Post. scrotal (labial) a. – in superficial pouch
2. Dorsal artery of penis (clitoris) – through
 supplies superficial penis / clitoris
& has two branches:
3. Deep artery of penis (clitoris) –terminal branch of
perineal artery = serves the crus & corpora cavernosum
a) Artery of bulb of penis (vestibular bulb) – in
deep pouch to serve corpus spongiusum
b) Urethral a. – indeep pouch serves urethra
f) Additional anterior trunk branches in women:
1. Uterine a –through broad ligament
a) ascends lat. to uterine wall to uterine tubes
 anastomizes w/ ovarian a.
b) descends lat to vaginal wall 
2. vaginal a– to vagina & anastomizes w/ uterine artery
g) Inferior gluteal a – terminal branch of anterior trunk
exits in gr sciatic f., inf to piriformis
1. Median sacral a – @ bifurcation of abdominal aorta,
descends in midline ant to sacrum,
anastomizes w/ iliolumbar and lat. Sacral arteries
2. Ovarian a. – in suspensory lig, anast. With ant branch
of int. iliac
3. Ext. pudendal a. – from femoral artery
courses medially to serve anterior perineum skin
1. Most veins follow arteries  internal iliac v.
2. Pelvic plexuses of veins – networks of veins on surfaces
of most pelvic viscera:
a) Dorsum vein of penis (clitoris) – parallels dorsal
artery of penis/clitoris 
b) Prostatic (vesical) venous plexus – prostate & bladder

c) External rectal plexus –
subcutaneous around
perianal skin
 inf rectal v. (external
anal sphincter)  middle rectal v  internal iliac v.
1. Internal rectal plexus –
rectum v. 
in submucsa of anal canal
drains into superior
inf mesenteric  hepatic portal
system
2. Gonadal (testicular
or ovarian) v a) left 
b) right 
3. Median sacral v.
1. Visceral lymphatics:
a) int. & ext. iliac nodes 
b) common iliac nodes 
c) lateral aortic & preaortic nodes 
d) lumbar trunks 
e) thoracic duct –
2. Perineum lymphatics:
a) superficial penis & scrotum (clitoris & labium
major)  Superficial inguinal nodes  ext. iliac
nodes
b) glans penis, glans clitoris, labia minora, inferior
vagina deep inguinal nodes external iliac nodes
c) testes: spermatic cord  post abdominal wall 
lateral aortic & prearotic nodes
d) ovaries, uterus, uterine tubes: suspensory ligament 
post abdominal wall  lateral aortic & preaortic nodes
e) deep perineum internal iliac nodes  CI nodes