Axillary Nerve Palsy

Axillary nerve injury is an uncommon condition which results in weakness of the deltoid muscle and numbness on the side of the shoulder. Nerves carry signals from the brain to maintain and communicate with skeletal muscles, causing them to contract on demand. When the nerve to a specific muscle is injured, the muscles innervated (controlled) by that nerve are affected, then weaken and atrophy (muscle wasting). Axillary nerve injury is typically caused by a direct impact to the shoulder or excessive stretching associated with a shoulder dislocation or fracture.