sacral plexus Flashcards
what is the spinal root value of the sacral plexus
anterior fibres of S1-S4
what nerves originate from the sacral plexus
superior gluteal inferior gluteal sciatic posterior femoral cutaneous pudendal nerve
what muscle does the sacral plexus sit on
piriformis
what foramen do most of the nerves pass through
greater sciatic
root value of superior gluteal nerve
L4-S1
what muscles does the superior gluteal nerve innervate
gluteus minimus
gluteus medius
tensor fascia lata
what is the root value for the inferior gluteal nerve
L5-S2
what muscle does the inferior gluteal nerve innervate
gluteus maximus
what is the root value for the sciatic nerve
L4-S3
what muscles does the sciatic nerve innervate
all muscles in posterior compartment of thigh, leg and sole of foot
what areas of skin does the sciatic nerve supply
tibial branch - posterolateral leg, lateral foot, sole of foot
common fibular - lateral leg, dorsum of foot
what is the root value of the posterior femoral cutaneous nerve
S1-S3
what area of skin does the posterior femoral cutaneous nerve innervate
posterior surface of thigh and leg
perineal branch innervates most skin of perineum
root value of pudendal nerve
S2-S4
what muscles does the pudendal nerve innervate
skeletal muscles in perineum
external anal sphincter
external urethral sphincter
levator ani
what area of skin does the pudendal nerve innervate
penis
clitoris
skin around anus
anal canal
what foramina does the pudendal nerve pass through
greater sciatic foramen
lesser sciatic foramen
what ligament does the pudendal nerve cross to go from the greater to lesser sciatic foramen
sacrospinous ligament
what forms the pudendal canal
the fascia of the obturator internus
where is the pudendal canal
inner aspect of ischium
below obturator foramen
moves posterior to anterior
what are the contents of the pudendal canal
internal pudendal artery and veins
pudendal nerve
what branches does the pudendal nerve give off in the pudendal canal
inferior rectal
perineal nerve
what does the pudendal nerve continue as in the pudendal canal
dorsal nerve of penis or clitoris
what muscles does the perineal nerve inervate
levator ani muscles
bulbospongiosus
ischiocavernosus
what does the dorsal nerve innervate
skin of penis or clitoris
what anatomical pathway does the pudendal nerve take
goes through greater sciatic foramen anterior to piriformis
follows ischial spine to enter pelvis again through the lesser sciatic foramen and supplies the perineum
describe the anatomical pathway of the superior gluteal nerve
passes through greater sciatic foramen over piriformis to supply gluteus medius and minimus
describe the anatomical pathway of the inferior gluteal nerve
passes under piriformis through greater sciatic foramen to supply gluteus maximus
describe the anatomical pathway of the obturator nerve
from lumbar plexus
runs along lateral wall of pelvis
enters obturator canal over the top of psoas major and exists the pelvis to supply the medial thigh
obturator nerve route
L2-4
superior and inferior gluteal nerve routes
L4-S1 sup
L5-S2 inf
where does autonomic innervation of the pelvis come from
sacral and lumbar sympathetic trunks (located medial to spinal nerves)
what nerve innervates the skin of the external genitalia
ilioinguinal
what effect do parasympathetic nerves have on bladder, rectum and penis
contracts bladder
contracts rectum
erection
what nerves cause ejaculation
sympathetic
point and shoot
para for erection, symp for ejaculation
