Most commonly seen as a result of shoulder dystocia during vaginal delivery in the newborn where there is forced depression of the shoulder produces damage to the upper plexus, giving prominent weakness of the deltoid, biceps, and other proximal muscles.
- Damage to the upper roots of the brachial plexus
- When the head is forced away from the ipsilateral shoulder
- A C5/C6 lesion during trauma or childbirth
- Other causes are direct trauma - knife, gunshot
- Upper roots are stretched or damaged
- The waiter's or more a bellboy's tip position
- Sensory loss over the lateral aspect of the upper arm (deltoid paralysis)
- Paralysis of shoulder abduction, and paralysis of the biceps, brachialis and coracobrachialis.
- In addition to the loss of elbow flexion, the biceps is also a powerful supinator of the forearm, so the forearm assumes a pronated position.
- The arm may be held in adduction, with the fingers pointing backwards, so-called waiter's tip position. Distal strength in the upper extremity remains intact.
- Brachial plexus injury also may be associated with Horner's syndrome, a fractured clavicle or humerus, subluxation of the shoulder or cervical spine, cervical cord injury, and facial palsy
- Brachial plexus injury may also be associated with phrenic nerve injury and diaphragmatic paralysis which may need respiratory support in newborn
- Brain injury or cerebral palsy
- Imaging and EMG/Nerve Conduction studies may be needed as well as plain films
- The affected arm is usually painful and should be immobilized across the upper abdomen for 7-10 days. Passive physiotherapy.
- The lesion may resolve with time depending on the severity. Physiotherapy may be needed
- Some may need corrective surgery including Nerve transfers (usually from the opposite arm or limb), Sub Scapularis releases and Latissimus Dorsi Tendon Transfers.