GROSS ANATOMY

Detailed explanation-1: -A severe upper-trunk injury may paralyze the shoulder muscles (deltoid muscle and rotator cuff), as well as the muscle in the upper arm (biceps.) When a fall forces the shoulder down and the head to the opposite side, upper-trunk palsy can result. This illustration shows a left plexus.

Detailed explanation-2: -Erb’s palsy affects the shoulder, arm and elbow. In general, your hand muscles aren’t affected, but your hands may experience tingling or numbness. Signs and symptoms of Erb’s palsy include: Paralysis or limpness of the shoulder, arm and elbow.

Detailed explanation-3: -Erb’s palsy: a common injury of the upper brachial plexus nerves, causing numbness and loss of motion around the shoulder and an inability to flex the elbow, lift an arm or bring objects to the mouth.

Detailed explanation-4: -The muscles that most often are responsible for impingement upon the brachial plexus are the scalenes, pectoralis minor, and subclavius. Muscles of the arm occasionally impinge upon branches of the brachial plexus.