Brachial Plexus Injury Overview

Brachial Plexus Injury

• The brachial plexus is a network of nerves that provides movement and feeling to the shoulder, arm, and hand.
• Nerves supporting the arm exit the spinal column high in the neck. Those supporting the hand and fingers exit lower in the neck.
• The brachial plexus is composed of four cervical nerve roots (C5-C8) and the first thoracic nerve root (T1).
• These nerve roots combine to form three trunks:
  • C5-C6 form the upper trunk.
  • C7 continues as the middle trunk.
  • C8-T1 form the lower trunk.
• Each trunk divides into a division: half supply flexor muscles and the other half supply extensor muscles.

Causes of Brachial Plexus Injury

• Brachial plexus birth injuries happen during the delivery process. This can lead to incomplete sensory and/or motor function in the arm.
• A brachial plexus injury occurs in approximately 1.5 out of every 1,000 live births.
• Traumatic brachial plexus injuries can result from motor vehicle accidents, bike accidents, ATV accidents, sports, etc., and involve various severities of nerve damage from a mild stretch to a complete tear from the spinal cord.

Types of Brachial Plexus Injuries

• Avulsion: The nerve is torn away from its spinal cord attachment. This is the most severe type, and often results in an eyelid droop (Horner's syndrome) for a lower brachial plexus injury.
• Rupture: The nerve is torn, but not at its attachment to the spinal cord.
• Neuroma: Scar tissue forms around the injury site, putting pressure on the nerve and preventing signals to the muscles.
• Neurapraxia: The nerve is stretched and damaged, but not torn.

Conditions Related to Brachial Plexus Injuries

• Erb-Duchenne's Palsy: Paralysis of the arm caused by injury to the upper brachial plexus nerves (C5-C6). It occurs because of difficult childbirth, shoulder dystocia, sports injuries, falls, or accidents.
  • Symptoms include muscle weakness & paralysis in the affected muscles, the arm hanging limply, internally rotated with a downward-bent wrist ("waiter's tip"), difficulty lifting the arm, bending the elbow and reduced sensation in the outer arm & thumb.
• Klumpke's Palsy: Injury to lower brachial plexus nerves (C8-T1). Causes include breech births, falls, pulling injuries, or accidents causing arm hyperextension.
  • Symptoms include muscle weakness & paralysis in the forearm and hand muscles, claw hand position (hyperextension of the metacarpophalangeal joints with flexion of the interphalangeal joints), and reduced sensation in the medial aspect of the arm, forearm and hand (ring & little fingers).

Axillary Neuropathy

• Injury to the axillary nerve (C5-C6). Common causes include shoulder dislocations or fractures, especially of the humerus.
• Symptoms include muscle weakness and atrophy (particularly in the deltoid muscle), making it difficult to lift the arm, decreased sensation over the shoulder (regimental badge area).
• Treatment involves physical therapy for strengthening and range of motion exercises. Occupational therapy is important for adapting daily living activities. Surgery may be used.

Radial Neuropathy

• Injury to the radial nerve. Causes include fractures (especially of the humerus), prolonged pressure (e.g., during sleep or incorrect positioning), or direct injuries.
  • Symptoms include wrist drop (inability to extend the wrist and fingers), weakness in the arm, numbness or tingling along the back of the hand and forearm,
• Treatment involves splinting, physical therapy, medications for pain relief, and in severe cases, surgery.

Median Neuropathy

• Damage or compression to the median nerve, affecting forearm, hand and fingers.
  • Causes include carpal tunnel syndrome (compression in the wrist), or fractures around the wrist or forearm, or repetitive motion injuries.
    • Symptoms include hand weakness (difficulty with pinch grip), numbness/tingling along the thumb, index, middle fingers and half of the ring finger, and/or pain radiating from the wrist to the hand and fingers especially at night.
  • Treatment may involve splinting, corticosteroid injections, physical therapy, and in severe cases, carpal tunnel release surgery.

Carpal Tunnel Syndrome

• A condition caused by compression of the median nerve within the carpal tunnel.
• Causes include anatomical factors (narrowing of the carpal tunnel), repetitive motion activities, pregnancy (hormonal changes), and anatomical changes.
  • Symptoms: numbness and tingling in the thumb, index, middle and half of the ring finger. Pain may be burning or aching and can get worse at night.
  • Treatment often begins with wrist splinting. Corticosteroid injections or physical therapy are also used. Surgery is a last resort.

Ulnar Neuropathy

• Damage or compression of the ulnar nerve, affecting sensation and movement in the forearm, hand, and fingers.
  • Common causes include compression at the elbow (cubital tunnel syndrome), wrist (Guyon's canal syndrome), trauma or direct injury to the nerve, or prolonged pressure or overuse.
    • Symptoms include claw hand deformity (hyperextension of metacarpophalangeal joints, flexion of interphalangeal joints of the ring and little fingers), weakness (grip strength and fine motor skills are difficult), and numbness/tingling in the ring and little fingers along the ulnar border of the hand and forearm.
  • Treatment may involve splinting, physical therapy, activity modification or if severe or refractory cases, surgery.

Diagnosis of Brachial Plexus Injuries

• Clinical examination (muscle strength, sensory function, reflexes).
• Provocative tests (Tinel's sign, Phalen's test).
• Imaging studies (MRI, CT myelography, ultrasound).
• Electrodiagnostic studies (EMG, NCS).
• Correlation of clinical findings with imaging and electrodiagnostic results for a comprehensive diagnosis.

Prognosis & Outcomes

• Factors affecting recovery: severity of injury, timeliness of treatment, and patient's age and health.
• Possible outcomes: full recovery, partial recovery, or permanent disability.