Radial nerve - axillary lesions

Causes

• Lesion in posterior cord of brachial plexus.
• Compression high in the axillary region (eg. cruches, missile trauma, shoulder dislocation).
• Softball players’ “windmill pitching”.

Symptoms & signs

• Elbow extension weakness.
• Triceps atrophy with hyporeflexia or areflexia.
• Radial hyporeflexia or areflexia.
• Wrist drop.
• Forearm supination weakness.
• Extension weakness in all five metacarpophalangeal joints.
• Extension and abduction weakness in interphalangeal joint of thumb.
• Abduction weakness of all fingers (because of lack of synergistic wrist flexion to the action of the dorsal interossei) may be mistaken for ulnar nerve involvement.
• Sensory deficit and paresthesias in the extensor surface of arm, forearm, hand and first 4 fingers.