Peripheral Nerves

Question 1

Axillary

Answer 1

Branch of posterior cord of brachial plexus
C5-C6
Teres minor and deltoid
skin covering lower half of deltoid and upper part of long head of triceps

Question 2

What are causes of injury to axillary nerve?

Answer 2

Shoulder dislocation
Fracture of surgical neck of humerus
“Square shoulder” = deltoid atrophy

Question 3

Radial

Answer 3

Branch of posterior cord of brachial plexus
C5-C8, T1
Triceps, anconeus, brachioradialis, supinator, and ECR, ECU, ED, EDM, EPL, EPB, EI, APL
Sensory: skin of lower half of lateral arm, skin of back of arm, skin of back of forearm, skin of lateral half of dorsum of hand and lateral two and half digits including thumb

Question 4

Radial nerve injury

Answer 4

Radial tunnel syndrome
Posterior interosseous nerve syndrome
Wrist drop

Question 5

Ulnar nerve

Answer 5

Branch of medial cord of brachial plexus
C7-T1
Dorsal interossei, palmar interossei, adductor pollicis, opponens digiti minimi, flexor digiti minimi, abductor digiti minimi
Flexor pollicis brevis, flexor digitorum profundus, flexor carpi ulnaris, lumbricals
Sensory: medial 1/2 of palm, dorsal aspect of medial one and half fingers, 1/2 of 4th, 5th digit

Question 6

Ulnar nerve lesion

Answer 6

Cubital tunnel syndrome
Guyon’s Canal syndrome
Ulnar claw hand

Question 7

Cubital tunnel syndrome

Answer 7

compression at cubital tunnel of elbow
Paralysis of flexor carpi ulnaris, flexor digitorum profundus, hypothenar eminence, interossei, and 3rd/4th lumbricals

all sensations affected
inability to grip paper

Question 8

Guyon’s Canal Syndrome

Answer 8

sensory changes and progressive weakness of muscles innervated distal to Guyon’s canal

Question 9

Ulnar claw hand

Answer 9

hyperextension of 4th, 5th MCP, flexion of 4th, 5th IP due to weakness of lumbricals and interossei

Question 10

Median nerve

Answer 10

Formed from medial and lateral cord of brachial plexus
C5-C8, T1
Enters hand via carpal tunnel

Motor: Flexor digitorum profundus, flexor policis longus, pronator quadratus, abductor pollicis brevis, pronator teres, opponens pollicis, palmaris longus, lumbricals 1,2, flexor carpi radialis, flexor digitorum superficialis, flexor pollicis brevis

Sensory: skin of lateral 2/3 of palm, dorsal tips of 1, 2, 3 finger palmar skin of lateral three and half fingers

Question 11

Median nerve injuries

Answer 11

Pronator teres syndrome
Carpal tunnel syndrome
Ape hand deformity

Question 12

Pronator teres syndrome

Answer 12

hypertrophy of pronator teres muscle can compress the median nerve
Pronator teres normal but other muscles supplied by median nerve and sensory distribution is affected

Question 13

Carpal tunnel syndrome

Answer 13

median nerve is compressed under the flexor retinaculum of the wrist

Question 14

ape hand deformity

Answer 14

wasting of thenar eminence of the hand due to median nerve palsy

Question 15

Musculocutaneous nerve

Answer 15

Branch of lateral cord of brachial plexus
C5-7
Motor: biceps, brachialis, coracobrachialis
Sensory: skin of lateral side of forearm

Question 16

Suprascapular nerve

Answer 16

Arises from upper trunk of brachial plexus
C5-C6
Motor: infraspinatus, supraspinatus

Question 17

Subscapular nerve (upper & lower)

Answer 17

Branch of posterior cord of brachial plexus
C5-C6
Motor: teres major (lower), subscapularis (upper and lower)

Question 18

Lateral pectoral nerve

Answer 18

Branch of lateral cord of brachial plexus
C5-C7
Motor: pec major

Question 19

Medial pectoral nerve

Answer 19

Branch of medial cord of brachial plexus
C8, T1
Motor: Pec minor

Question 20

Long thoracic nerve

Answer 20

Arises from root of brachial plexus
C5, 6, 7
Motor: serratus anterior
Injury: winged scapula

Question 21

Thoracodorsal nerve

Answer 21

Branch of posterior cord of brachial plexus
C6-8
Motor: lats

Question 22

Dorsal scapular nerve

Answer 22

Ares from root of brachial plexus
C5
Motor: Rhomboids, levator scapulae

Question 23

Nerve to subclavius

Answer 23

Arise from upper trunk of brachial plexus
C5-C6
Motor: subclavius

Question 24

Spinal Accessory Nerve (CN X1)

Answer 24

Motor supply: trapezius, sternocleidomastoid

Question 25

Superior gluteal nerve

Answer 25

L4-S1 Motor: glute med and min, TFL

Question 26

Inferior gluteal nerve

Answer 26

L5-S2 Motor: glute max

Question 27

Nerve to piriformis

Answer 27

L5-S2 Motor: piriformis

Question 28

Obturator nerve

Answer 28

L2-L4 Motor (anterior div): Adductors brevis and longus, gracilis Motor (posterior div): obturator externus, adductor magnus Sensory: skin of medial thigh

Question 29

Nerve to quadratus femoris

Answer 29

L4-S1 Motor: gemellus inferior, quadratus femoris

Question 30

Nerve to obturator internus

Answer 30

L5-S2 Motor: gemellus superior, obturator internus

Question 31

Sciatic nerve

Answer 31

Largest branch of sacral plexus L4-S2 Motor: Hamstrings, adductor magnus

Question 32

Femoral nerve

Answer 32

L2-L4 Passes through femoral triangle with femoral artery Motor: iliacus, pectineus, sartorius, quads Sensory: Medial lower 2/3 of thigh, front of thigh, medial leg

Question 33

Tibial nerve

Answer 33

Terminal branch of sciatic nerve L4-S3 Motor (superficial): gastroc, soleus, plantaris Motor (deep): Popliteus, tib posterior, FHL, FDL Sensory: skin over heel, lower posterolateral leg, medial side and lateral side of sole

Question 34

Medial plantar nerve

Answer 34

Branch of tibial nerve Motor: Abductor hallucis, FHB, FDB, lumbrical 1

Question 35

Lateral plantar nerve

Answer 35

Branch of tibial nerve Motor: plantar interossei, dorsal interossei, quadratus plantae, abductor digiti minimi, lumbrical s 2-4, adductor hallucis

Question 36

Common peroneal nerve

Answer 36

L4-S2 Originates from sciatic nerve at popliteal fossa Bifurcates into superficial and deep peroneal nerve

Question 37

Deep peroneal nerve

Answer 37

L4-S1 Motor: Tib ant, EHL, EDL, EDB, peroneus teritus Injury = foot drop and unopposed eversion during gait Sensory: webbing between 1st and 2nd toe on dorsal surface

Question 38

Superficial peroneal nerve

Answer 38

L4-S2 Motor: peroneus longus, peroneus brevis Sensory: dorsum of foot and anterolateral part of lower leg