Upper Extremity Neurology

Question 1

Supraclavicular nerve

Answer 1

Part of cervical plexus (Anterior rami of C1-4)
Provides cutaneous innervation to skin over neck and shoulder
Has middle, lateral and medial branches

Question 2

Brachial plexus

Answer 2

The roots of the plexus are the 5 anterior rami of C5-8 and T1, travel b/w the anterior and middle scalene muscles with the subclavian artery

Question 3

Dorsal scapular nerve innervates

Answer 3

Rhomboid major and minor

Question 4

Injury to superior part of brachial plexus

Answer 4

Typically affects C5/C6 anterior rami and are the result of dramatically increasing the angle between the neck and the shoulder. Patient will have adducted and medially rotated arm and an extended elbow
Also known as Erb-Duchenne palsy or “waiters tip position”

Question 5

Injury to inferior part of brachial plexus

Answer 5

Less common than upper portion injury, usually the result of dramatically increasing the angle between the trunk and upper limb
Can result in “claw hand” when the individual tries to make a fist, also known as klumpke paralysis

Question 6

The names of the posterior, lateral and medial cords are named because they are positioned posterior, lateral and medial to what

Answer 6

Axillary artery

Question 7

Medial pectoral nerve

Answer 7

Pierces the pectoralis minor, innervates both pectoral muscles

Question 8

Medial brachial cutaneous nerve

Answer 8

Sensory/cutaneous to medial aspect of the distal 2/3rds of brachium

Question 9

Medial antebrachial cutaneous nerve

Answer 9

Travels with ulnar nerve, then travels through deep fascia with basilic vein before dividing into anterior/posterior branches
Sensory from anterior and medial aspect of antebrachium

Question 10

Thoracodorsal nerve

Answer 10

Originates b/w upper and lower subscapular nerves

Innervates latissimus dorsi

Question 11

Lower subscapular

Answer 11

Innervates lower portion of subscapularis and the teres major

Question 12

Compression of brachial plexus

Answer 12

Usually results from prolonged periods of working with the upper limb extended over the head
Results in pain radiating down the arm, loss of sensation, tingling of the arms and weakness of hands

Question 13

Musculocutaneous nerve travels through what

Answer 13

Coracobrachialis

Question 14

Lateral antebrachial cutaneous nerve

Answer 14

Continuation of musculocutaneous nerve, sensory information from the lateral aspect of the antebrachium

Question 15

Musculocutaneous nerve injury

Answer 15

Rare but possible with blunt force trauma

Renders anterior brachial muscles paralyzed

Question 16

Axillary nerve path

Answer 16

Travels through quadrangular space with posterior humeral circumflex artery, produces superior lateral brachial cutaneous nerve, travels around surgical neck of humerus to deltoid

Question 17

Superior lateral brachial cutaneous nerve

Answer 17

Branch from axillary nerve

Sensory innervation from superior half of the lateral aspect of brachium

Question 18

Axillary nerve injury

Answer 18

Results in atrophy of the deltoid and loss of sensation over the superolateral arm

Question 19

Median nerve path

Answer 19

Travels through brachium with brachial artery, enters cubital fossa by passing through heads of pronator teres, travels through antebrachium between flexor digitorum profundus and superficialis, travels through carpal tunnel to central compartment of palm

Question 20

Anterior interosseous nerve path/muscles innervated

Answer 20

Travels along surface of interosseous membrane with anterior interosseous artery
Innervates lateral half of flexor digitorum profundus, flexor pollicis longus, pronator quadratus, then sends sensory fibers to innervate wrist joint

Question 21

Palmar cutaneous branch of median nerve

Answer 21

Originates before median nerve enters carpal tunnel, travels superficial to flexor retinaculum to provide sensory innervation from central palm

Question 22

Recurrent branch of median nerve

Answer 22

Innervates abductor pollicis, opponens pollicis, and superficial head of flexor pollicis brevis

Question 23

Medial branch of median nerve

Answer 23

Innervates 2nd lumbrical
Forms common palmar digital nerve which give sensory innervation to palmar surface and distal dorsal surface of digits 1, 2, 3 and lateral half of 4

Question 24

Lateral branch of median nerve

Answer 24

Innervates 1st lumbrical, becomes common palmar digital nerve which gives sensory innervation to palmar surface and distal dorsal surface of 1, 2, 3, and lateral half of digit 4

Question 25

Median nerve injury

Answer 25

Results in adducted thumb and thenar eminence atrophy, known as Apes hand. Injury to median nerve at elbow inhibits flexion of 2nd and 3rd digits, known as hand of benediction

Question 26

Ulnar nerve path

Answer 26

Terminal branch of medial cord, travels through medial brachium, passes through groove for ulnar nerve posterior to medial epicondyle, passes b/w two heads of flexor carpi ulnaris, travels through antebrachium b/w flexor carpi ulnaris and flexor digitorum profundus, becomes superficial as it enters hand passing over flexor retinaculum

Question 27

Muscular branches of ulnar nerve innervate

Answer 27

Flexor carpi ulnaris and medial half of flexor digitorum profundus

Question 28

Ulnar nerve provides sensory/cutaneous innervation to which parts of hand

Answer 28

Distal most anterior antebrachium and medial 1/3rd of palm
Dorsal aspect of 4th/5th digits
Palmar surface of medial half of 4th and 5th digits

Question 29

Deep ulnar nerve innervates

Answer 29

Abductor digiti minimi
Flexor digiti minimi
Opponens digiti minimi
3rd/4th lumbrical
Dorsal/palmar interossei
Adductor pollicis
Deep head of flexor pollicis brevis

Question 30

Ulnar nerve injury

Answer 30

Typically occurs in one of four places: posterior to the medial epicondyle, b/w the ulnar and humeral heads of flexor carpi ulnaris (cubital tunnel), at the wrist or in the hand.
Results in extensive loss of sensory and motor control in hand, and when patient tries to make fist it appears as claw hand

Question 31

Ulnar nerve compression

Answer 31

Can be compressed when pressure is placed on the hamulus of the hamate bone, like when riding a bike. This can produce sensory loss on the medial side of hand and weakness of intrinsic hand muscles referred to as handlebar neuropathy

Question 32

Radial nerve path

Answer 32

Travels to the posterior aspect of the humerus with deep brachial artery (both pass through triangular interval), passes b/w lateral and medial heads of triceps, divides in cubital fossa into deep/superficial branches

Question 33

Posterior brachial cutaneous and posterior antebrachial cutaneous

Answer 33

PBC- sensory from posterior brachium
PAbC- produces inferior lateral brachial cutaneous nerve, provides sensory from posterior antebrachium and inferior aspect of lateral brachium

Question 34

Muscular branches of the radial nerve innervate

Answer 34

Triceps
Anconeus
Brachioradialis
Extensor carpi radialis longus

Question 35

Deep radial nerve innervates

Answer 35

Extensor carpi radialis brevis
Supinator
Continues on as posterior interosseous after passing through the two heads of the supinator muscle

Question 36

Posterior interosseous nerve innervates

Answer 36

Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
Extensor indicis
Abductor pollicis longus
Extensor pollicis longus
Extensor pollicis brevis

Question 37

Superficial radial nerve provides sensory/cutaneous from

Answer 37

Lateral half of the dorsum of the hand
Dorsal aspect of thumb
Proximal aspect of dorsum of 2nd, 3rd and lateral half of 4th digits

Question 38

Injury of radial nerve

Answer 38

Results in “wrist drop”, impairment of elbow extension and thumb abduction/extension

Question 39

Thoracic spinal nerve- intercostobrachial nerve

Answer 39

Lateral cutaneous branch of the 2nd intercostal nerve, travels laterally to provide sensory/cutaneous innervation to uppermost medial aspect of brachium

Question 40

C5 dermatome

Answer 40

Over deltoid

Question 41

C6 dermatome

Answer 41

Lateral antebrachium and hand, including thumb

Question 42

C7 dermatome

Answer 42

Central portion of hand and posterior antebrachium, including 3rd digit

Question 43

C8 dermatome

Answer 43

Medial hand and antebrachium, including 5th digit

Question 44

T1 dermatome

Answer 44

Medial brachium

Question 45

T2 dermatome

Answer 45

Anterior border of axilla