Nerves of the Arm

C5

Motor:

• biceps flexion - C5, 6: musculocutaneous nerve
• deltoid - C5, 6: axillary nerve

Reflex:

• biceps

Sensation:

• lateral arm, above deltoid - axillary nerve

C6

Motor:

• biceps flexion - C5-C6 musculocutaneous nerve
• wrist extensors - C6-C7 radial nerve

Reflex:

• brachioradialis
• biceps

Sensation:

lateral forearm, thumb, index, half of middle finger - remember by making a "6" with these fingers

C7

Motor:

• triceps: C6,7,8 - radial nerve
• finger extension: C7 - radial nerve
• wrist flexors: C7 - median and ulnar nerves
• pronator teres: C6, 7 - median nerve

Reflex:

• triceps reflex

Sensation:

• middle finger

C8

Motor:

• finger flexion -
• finger abduction - C8, T1
• finger adduction C8, T1

Reflex:

none

Sensation:

• medial forearm, ring and little finger

T1

Motor:

• finger abduction - C8, T1
• finger adduction C8, T1

Reflex:

none

Sensation:

medial upper forearm and arm

musculocutaneous nerve

origins and path

• from C5,6,7
• travels within biceps and brachioradialis
• becomes lateral cutaneous nerve of forearm at elbow

musculature

• biceps brachii
• coracobrachialis
• brachialis

sensory

• lateral cutaneous nerve of forearm does just that

axillary nerve

origins

musculature

sensory

• superior lateral cutaneous nerve of arm - deltoid area

radial nerve

origins

musculature

• wrist extensors

sensory

• lateral dorsal hand

Saturday night palsy

median nerve

origins and path:

• from C5,6,7,8T1
• travels down centre of anterior arm

musculature

• pronator teres - pronation
• wrist flexors
• flexor pollicis brevis (thenar)

sensory

• lateral palm
• palmar surface of thumb and first 2.5 fingers

ulnar nerve

origins and pathway

• from C7,8,T1
• travels behind medial epicondyle

musculature

• flexor digitorum profundus
• flexor pollicis brevis
• palmar and dorsal interosseus muscles (abducsion/adduction)

sensory

• medial hand, with pinkie and 1/2 of ring finger