Clinical manifestations (1) Complete brachial plexus injury Motor deficits manifest as total paralysis of the hand, forearm and upper arm muscles. Sensory changes include loss of sensation in the hand, forearm, and part of the upper arm. Injuries to the proximal intervertebral foramen of cervical 8 and thoracic 1 may present with Horner’s syndrome. (2) Upper arm injury (Erb-Duchence type) This type is more common and is caused by injury to the cervical 5-6 nerve root at Erb’s point. This point is proximal to the suprascapular nerve and distal to the long thoracic and dorsal scapular nerves. The anterior serratus and rhomboid muscles are not affected. It is most often caused by trauma that separates the head and shoulder, subacromial shoulder pressure or birth injury. The patient’s deltoid, teres minor, supraspinatus and infraspinatus muscles are paralyzed along with the clavicular head of the pectoralis major, and the upper limbs are internally rotated due to the action of the latissimus dorsi and the sternal head of the pectoralis major. The biceps and brachioradialis were paralyzed, the anterior brachialis was weakened, and the elbow joint was straightened due to the action of the triceps. The posterior rotator and anterior rotator roundus are paralyzed, and the forearm is rotated anteriorly due to the action of the anterior rotator muscle. The radial wrist extensors are paralyzed and the hand is deflected to the ulnar side. Sensation is not affected by injury to the anterior branch of cervical 5. If cervical 6 is involved, there is numbness in the upper arm and lateral forearm. There is no Horner’s syndrome. (3) Lower brachial plexus injury (Klumpke type) is mainly cervical 8 thoracic 1 nerve root injury, mostly caused by excessive lifting or extension of the upper limb and excessive pulling of the trunk during arm position delivery. The main symptom is paralysis of the inner hand muscles with claw-like deformity. In the case of injury to the lower trunk of the brachial plexus, the flexors and extensors of the fingers are paralyzed. There is numbness of the ulnar side of the hand and forearm, and a small area of numbness on the medial side of the upper arm. Horner’s syndrome may be present.