Lumbosacral Plexus

Question 1

Largest nerve of the body

Answer 1

sciatic nerve

Question 2

roots of sciatic nerve

Answer 2

L4, L5, S1, S2, S3

Question 3

sciatic nerve innervates what muscles

Answer 3

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

Question 4

what muscles does sciatic nerve supply in gluteal region

Answer 4

sciatic nerve supplies no gluteal muscles

Question 5

tibial nerve innervates what muscles

Answer 5

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

Question 6

tibial nerve supplies foot soles via what branches

Answer 6

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

Question 7

tibial nerve damage results in what symptoms

Answer 7

Loss of:
plantar flexion
flexion of toes
weakened inversion

Question 8

variations of sciatic nerve

Answer 8

common fibular nerve pierces piriformis
common fibular nerve goes superior to piriformis
tibial and cfn both emerge from inferior part of piriformis

Question 9

sciatic nerve derivatives

Answer 9

tibular nerve and common fibular nerve

Question 10

common fibular nerve innervates what muscles

Answer 10

short head of biceps femoris

Question 11

cfn branches into what nerves (terminal branches)

Answer 11

superficial fibular nerve

deep fibular nerve

Question 12

superficial fibular nerve innervation

Answer 12

innervates:
fibularis longus
fibularis brevis
(both to evert foot)

skin of anterolateral leg and dorsum of foot

Question 13

deep fibular nerve innervation

Answer 13

innervates:
tibialis anterior - dorsiflex and invert foot
extensor digitorum longus - extend digits
extensor hallucis longus - extend big toe

skin between first and second toe

Question 14

cutaneous branches of cfn

Answer 14

sural communicating nerve

lateral sural cutaneous nerve

Question 15

lateral sural communicating nerve innervation

Answer 15

skin over upper lateral leg

Question 16

sural nerve innervation

Answer 16

skin over lower posterolateral leg

Question 17

sural communicating nerve + tibial nerve

Answer 17

sural nerve

Question 18

Fibular nerve damage leads to

Answer 18

Fibular Nerve Injury and foot drop

Question 19

Iliohypogastric nerve innervation

Answer 19

skin of anterior part of abdominal wall

Question 20

ilioinguinal nerve innervation

Answer 20

skin of groin, scrotum / labius majorus

abdominal muscles and skin of inguinal and pubic regions

Question 21

what is palpated in ilioinguinal nerve block

Answer 21

anterior superior iliac spine (ASIS) - 2cm medial and 2 cm superior from ASIS

Question 22

does ilioinguinal nerve provide visceral anesthesia?

Answer 22

no

Question 23

genitofemoral nerve branches into?

Answer 23

genital branch

femoral branch

Question 24

femoral branch innervation

Answer 24

skin of lateral femoral triangle (upper anterior thigh)

Question 25

genital branch innervation

Answer 25

sensory fxn: skin of anterior scrotum skin over mons pubis and labia majora motor fxn: cremastic muscle

Question 26

lateral femoral cutaneous nerve innervation

Answer 26

skin of anterolateral surface of thigh

Question 27

nerves with no motor function

Answer 27

lateral femoral cutaneous nerve | posterior femoral cutaneous nerve

Question 28

nerves with no sensory fxn

Answer 28

superior gluteal nerve

Question 29

femoral nerve innervation

Answer 29

innervates iliacus | flexors of hip and extensors of knee

Question 30

femoral nerve block location

Answer 30

2cm inferior of inguinal ligament (attached to ASIS)

Question 31

obturator nerve branches into

Answer 31

anterior and posterior branches

Question 32

obturator nerve (anterior branch) innervation

Answer 32

``` motor fibers to: adductor longus adductor brevis gracilis pectineus muscles (rare cases) ```

Question 33

posterior branch of obturator innervation

Answer 33

obturator externus and adductor magnus

Question 34

cutaneous branch of obturator innervation

Answer 34

skin in middle of medial part of the thigh

Question 35

obturator nerve damage symptoms

Answer 35

numbness and paraesthesis on medial aspect of thigh | weakness in thigh adduction

Question 36

What nerves constitutes lumbar plexus

Answer 36

``` I^2 Got Lunch on Friday Afternoons iliohypogastric ilioinguinal genitofemoral lateral femoral cutaneous thigh obturator nerve femoral nerve accessory obturator nerve ```

Question 37

what nerves comprises sacral plexus?

Answer 37

``` Superior gluteal nerve Inferior gluteal nerve Posterior femoral cutaneous nerve Pudendal nerve Sciatic nerve ```

Question 38

superior gluteal nerve innervation

Answer 38

primary hip abductors: gluteus medius gluteus minimus tensor fascia latae

Question 39

superior gluteal nerve damage results into

Answer 39

tredelenburg gait weakened abduction of thigh COG over supporting lower limb

Question 40

inferior gluteal nerve innervation

Answer 40

gluteus maximus

Question 41

ign injury leads into

Answer 41

gluteus maximus gait

Question 42

posterior femoral cutaneous nerve innervation

Answer 42

skin of inferior half of buttocks skin over posterior thigh and popliteal fossa skin of lateral perineum and upper medial thigh

Question 43

what nerve supplies more skin than any other cutaneous nerve

Answer 43

posterior femoral cutaneous nerve

Question 44

Pudendal nerve innervation

Answer 44

motor: perineum muscles sensory: majority of perineal region via inferior rectal and perineal nerves and dorsal nerve of clitoris or penis

Question 45

pudendal nerve branches into

Answer 45

inferior rectal nerve perineal nerve dorsal nerve of penis or clitoris

Question 46

perineal nerve innervation

Answer 46

muscles of perineum and pelvic floor bulbospongiosus ischiocavernosus Levator ani (puborectalis, pubococcygeus, iliococcygeus)