A complex neurological network formed by the spinal nerve roots of C5-T1. The nerves form three cords, which subsequently form five terminal nerve branches, together supplying the upper limb.
Musculocutaneous nerve
Nerve roots - C5/C6/C7
Sensation - lateral forearm
Motor - Biceps and brachialis - flexion and supination of the elbow
Clinical features: Loss of elbow flexion, loss of biceps reflex
Axillary nerve
Nerve roots - C5/C6
Sensation - Regimental badge - lower deltoid
Motor - Deltoid and teres minor - abduction, flexion and ER of the shoulder
Causes of Injury:
Anterior shoulder dislocation
Fracture of the neck of the humerus
Clinical features: Loss of shoulder abduction, regimental badge numbness
Radial nerve
Nerve roots - C5/C6/C7/C8/T1
Sensation - Posterior arm and forearm, lateral 2/3rd of dorsal hand and fingers
Motor - Triceps - elbow extension
Causes of Injury:
Fracture of proximal humerus
Fracture of radius
Saturday night palsy - falling asleep with arm over back of chair
Clinical features:
Loss of elbow extension, wrist extension, absent triceps reflex, loss of sensation over posterior forearm/arm
Wrist drop - cannot extend wrist/fingers → unopposed flexion
Median nerve
Nerve roots - C5/C6/C7/C8/T1
Sensation - Hand - thenar eminence, lateral 2/3 palm and lateral 3.5 fingers
Motor - anterior compartment of forearm - wrist flexion and abduction, pronation of forearm, LOAF muscles of hand
Causes of Injury:
Carpal tunnel syndrome
Supracondylar humeral fractures
Clinical features:
Hand of benediction, loss of sensation/motor as above
