Lumbosacral Plexus Flashcards
Largest nerve of the body
sciatic nerve
roots of sciatic nerve
L4, L5, S1, S2, S3
sciatic nerve innervates what muscles
Posterior thigh muscles: Innervated by tibial nerve: Long head of Biceps femoris Semimembranosus Semitendinosus hamstring portion of adductor magnus
innervated by common fibular nerve
short head of biceps femoris
all leg and foot muscles
skin of most leg and foot
articular branches to all joints of the lower limb
what muscles does sciatic nerve supply in gluteal region
sciatic nerve supplies no gluteal muscles
tibial nerve innervates what muscles
Superficial component (PSG):
Plantaris - flexes ankle
Soleus - flexes ankle
Gastrocnemius - flexes ankle and knee
Deep compartment (PFFT):
Popliteus - lateral rotation of femur on tibia to unlock knee
Flexor Hallucis Longus - flexes big toe and ankle flexion
Flexor digitorum longus - flexes other digits
tibialis posterior - inverts foot and flexes ankle
tibial nerve supplies foot soles via what branches
Medial calcaneal branch - supplies skin of heel
Medial plantar nerve - supplies medial 3 1/2 digits
Lateral plantar nerve - innervates lateral 1 1/2 digits
tibial nerve damage results in what symptoms
Loss of:
plantar flexion
flexion of toes
weakened inversion
variations of sciatic nerve
common fibular nerve pierces piriformis
common fibular nerve goes superior to piriformis
tibial and cfn both emerge from inferior part of piriformis
sciatic nerve derivatives
tibular nerve and common fibular nerve
common fibular nerve innervates what muscles
short head of biceps femoris
cfn branches into what nerves (terminal branches)
superficial fibular nerve
deep fibular nerve
superficial fibular nerve innervation
innervates:
fibularis longus
fibularis brevis
(both to evert foot)
skin of anterolateral leg and dorsum of foot
deep fibular nerve innervation
innervates:
tibialis anterior - dorsiflex and invert foot
extensor digitorum longus - extend digits
extensor hallucis longus - extend big toe
skin between first and second toe
cutaneous branches of cfn
sural communicating nerve
lateral sural cutaneous nerve
lateral sural communicating nerve innervation
skin over upper lateral leg
sural nerve innervation
skin over lower posterolateral leg
sural communicating nerve + tibial nerve
sural nerve
Fibular nerve damage leads to
Fibular Nerve Injury and foot drop
Iliohypogastric nerve innervation
skin of anterior part of abdominal wall
ilioinguinal nerve innervation
skin of groin, scrotum / labius majorus
abdominal muscles and skin of inguinal and pubic regions
what is palpated in ilioinguinal nerve block
anterior superior iliac spine (ASIS) - 2cm medial and 2 cm superior from ASIS
does ilioinguinal nerve provide visceral anesthesia?
no
genitofemoral nerve branches into?
genital branch
femoral branch
femoral branch innervation
skin of lateral femoral triangle (upper anterior thigh)
genital branch innervation
sensory fxn:
skin of anterior scrotum
skin over mons pubis and labia majora
motor fxn:
cremastic muscle
lateral femoral cutaneous nerve innervation
skin of anterolateral surface of thigh
nerves with no motor function
lateral femoral cutaneous nerve
posterior femoral cutaneous nerve
nerves with no sensory fxn
superior gluteal nerve
femoral nerve innervation
innervates iliacus
flexors of hip and extensors of knee
femoral nerve block location
2cm inferior of inguinal ligament (attached to ASIS)
obturator nerve branches into
anterior and posterior branches
obturator nerve (anterior branch) innervation
motor fibers to: adductor longus adductor brevis gracilis pectineus muscles (rare cases)
posterior branch of obturator innervation
obturator externus and adductor magnus
cutaneous branch of obturator innervation
skin in middle of medial part of the thigh
obturator nerve damage symptoms
numbness and paraesthesis on medial aspect of thigh
weakness in thigh adduction
What nerves constitutes lumbar plexus
I^2 Got Lunch on Friday Afternoons iliohypogastric ilioinguinal genitofemoral lateral femoral cutaneous thigh obturator nerve femoral nerve accessory obturator nerve
what nerves comprises sacral plexus?
Superior gluteal nerve Inferior gluteal nerve Posterior femoral cutaneous nerve Pudendal nerve Sciatic nerve
superior gluteal nerve innervation
primary hip abductors:
gluteus medius
gluteus minimus
tensor fascia latae
superior gluteal nerve damage results into
tredelenburg gait
weakened abduction of thigh
COG over supporting lower limb
inferior gluteal nerve innervation
gluteus maximus
ign injury leads into
gluteus maximus gait
posterior femoral cutaneous nerve innervation
skin of inferior half of buttocks
skin over posterior thigh and popliteal fossa
skin of lateral perineum and upper medial thigh
what nerve supplies more skin than any other cutaneous nerve
posterior femoral cutaneous nerve
Pudendal nerve innervation
motor: perineum muscles
sensory: majority of perineal region via inferior rectal and perineal nerves and dorsal nerve of clitoris or penis
pudendal nerve branches into
inferior rectal nerve
perineal nerve
dorsal nerve of penis or clitoris
perineal nerve innervation
muscles of perineum and pelvic floor
bulbospongiosus
ischiocavernosus
Levator ani (puborectalis, pubococcygeus, iliococcygeus)
