Lower extremity injuries (Lumbosacral plexus)

Question 1

Mechanism of injury for superior gluteal nerve

Answer 1

IM injection to upper medial gluteal region

Question 2

Complications of lunate fracture

Answer 2

Cmopressoin of median nerve (carpal tunnel syndrome)

Question 3

Landmark used for pudendal nerve block during childbirth

Answer 3

Ischial spine

Question 4

Femoral nerve sensory + motor innervation

Answer 4

Sensory: Anterior thigh + medial leg/ foot

Motor: Quadriceps + iliopsoas

Question 5

Why does thenar eminence atrophy but sensation spared in carpal tunnel syndrome

Answer 5

Palmar cutaneous branch from median nerve enters hand external to the carpal tunnel

Question 6

Nerve affected in colles fracture

Answer 6

Median nerve

Question 7

Iliohypogastric nerve

Answer 7

T12-L1

Question 8

Sensory + motor innervation of pudendal nerve

Answer 8

Sensory- perineum

Motor- external urethral + anal sphincters

Question 9

Presentation of common peroneal nerve injury

Answer 9

Foot drop (deep peroneal nerve) + foot inveresion (superficial peroneal nerve)

Loss of sensation on dorsum of foot

Steppage gait- exaggerated hip and knee flexion due to foot drop

Question 10

Obturator nerve motor + sensory innervations

Answer 10

Sensory: Medial thigh

Motor:

• Adductors (adductor longus, brevis, magnus): adducts thigh at the hip
• Gracilis: Adducts thigh at hip, flexes leg at knee, helps rotate knee medially (crosses knee while seated)

Question 11

Tibial nerve

Answer 11

L4-S3

Question 12

Nerve affected in supracondylar fracture

Answer 12

Median + possibly radial

(Also brachial artery)

Question 13

Mechansim of injury to common peroneal nerve

Answer 13

Fibular neck fracture blow to leg, compressoin of lateral aspect of leg (e.g. tight leg casts, prolonged lying during surgery)

Question 14

Mechanisms of sciatic nerve injury

Answer 14

Herniated disc, posterior hip dislocation (most common)

Question 15

Sciatic nerve sensory + motor innervations

Answer 15

Sensory: posterior thigh + leg

Motor: muscles of posterior thigh / hamstringes; extends thigh at hip, flexes leg at knee

Question 16

Nerves of femoral nerve

Answer 16

L2-L4

Question 17

Sensory + motor innervation of tibial nerve

Answer 17

Sensory: sole of foot

Motor:

posterior compartment muscles- plantarflexes foot, inverts foot

Foot flexor muscles

Question 18

Signs + sx of femoral nerve injury

Answer 18

Motor: Weak hip flexion (iliopsoas), Loss of knee extension + Atrophy of quads

Sensory loss: Loss of sensation in anterior thigh/ medial leg/foot

Quadriceps gait

Question 19

Iliohypogastric nerve motor + sensory innervation

Answer 19

Sensory: suprapubic region

Motor: transversus abdominis + internal oblique

Question 20

Signs + sx of carpal tunnel syndrome

Answer 20

Compression of median nerve leads to paresthesia, pain, numbness in distribution of median nerve

Thenar eminence atrophy but sensation is spared (palmar cutnaeous branch enters hand extenral to carpal tunneL)

Question 21

Signs + sx of inferior gluteal nerve injury

Answer 21

Difficulty climbing stairs, rising from seated position (loss of hip extension)

Gluteus maximus gait: pt keeps weight back during heel strike to prevent body from swinging forward due to momentum

Question 22

Mechansim of injury to tibial nerve

Answer 22

Knee trauma + Baker cysts (proximal lesion)

Tarsal tunnel syndrome (distal lesion)

Question 23

Mechanism of femoral nerve injury

Answer 23

• Pelvic fracture
• Spontaneous retroperitoneal hematoma (psoas muscle)- leads to femoral nerve compression

Question 24

Mechanism of inferior gluteal nerve injury

Answer 24

Posterior hip dislocation

Question 25

Presentation of tibial nerve injury

Answer 25

All of muscles in back of leg + sole of foot paralyzed- opposing muscles dorsiflex foot at ankle + evert the foot (can't stand on tiptopes) Inability to curl toes Loss of sensation on sole

Question 26

Common peroneal nerve

Answer 26

L4-S2

Question 27

Nerves of obturator nerve

Answer 27

L2-L4

Question 28

Signs + sx of sciatic nerve injury

Answer 28

Sensory: below knee involves entire peroneal, tibial, sural territories (most significant finding) Motor: Foot drop, wasting of calf muscles, loss of Achilles reflex (paralysis of muscles supplied by tibial + common peroneal nerves)

Question 29

Signs + sx of superior gluteal nerve injuy

Answer 29

Positive Tredelengberg gait: inability to keep pelvis level when standing on one foot or during gait; lesion is contralateral to the side of hip that drops

Question 30

Mechanism of injury of pudendal nerve + presentation

Answer 30

Mechanism: strethc injury during childbirth Presentation: decreased sensation in perineum + genital area; can cause fecal or urinary incontinence

Question 31

Inferior guteal nerve sensory + motor innervation

Answer 31

Sensory: none Motor: gluteus maximus; major extensor of hip joint

Question 32

Sciatic nerve

Answer 32

L4-S3 Two nerves (tibial nerve + common peroneal nerve) that separate just proximal to popliteal fossa

Question 33

Nerves of superior gluteal nerve

Answer 33

L4-S1

Question 34

Pudendal nerve

Answer 34

S2-S4

Question 35

Signs + sx of obturator nerve injury

Answer 35

Loss of sensation in medial thigh + loss of thigh adduction

Question 36

Description of posterior hip dislocation

Answer 36

Right hip flexed, internally rotated, adducted

Question 37

Nerves of inferior gluteal nerve

Answer 37

L5-S2

Question 38

Superior gluteal nerve sensory + motor innervation

Answer 38

Sensory: none Motor: Gluteus minimus + medius-- keeps pelvis level when opposite level off the ground

Question 39

Common peroneal nerve sensory + motor innervation

Answer 39

Sensory: dorsum of foot, lateral portion of lower leg Motor: - deep peroneal nerve- anterior compartment of leg; dorsiflexion of foot + extension of toes - Superficial peroneal nerve- lateral comparment of leg; everts foot

Question 40

Mechansim of injury of iliohypogastric nerve + presentation

Answer 40

Abdominal surgery; burning or tinglign pain in surgical incision site radiating to inguinal/suprapubic region