Brachial Plexus injury

• Excessive lateral traction on the neck during delivery → injury to the upper trunk of the brachial plexus → Erb palsy (most common iatrogenic brachial plexus injury during delivery)

• Excessive traction on the arm during delivery → injury to the lower trunk of the brachial plexus → Klumpke palsy

Prognosis: approx. 25% of affected infants experience persistent functional impairment

• Injury to the upper trunk of the brachial plexus (C5–C6)

• Etiology

  • Excessive lateral flexion of the neck

    • Trauma (e.g., falling on the head and shoulder in a motorcycle accident)

    • Birth injury: excessive lateral traction on the neck during delivery and shoulder dystocia

• Clinical features

  • Weakness of muscles in the C5 and C6 myotomes → flexed wrist with an extended forearm and internally rotated and adducted arm (waiter's tip posture)

    • Weak biceps brachii, brachialis, and brachioradialis

      • Impaired flexion and supination of the forearm

      • Absent biceps reflex

    • Weak infraspinatus and supraspinatus → impaired external rotation of the arm

    • Weak deltoid and supraspinatus → impaired arm abduction

    • Weak wrist extensors → impaired wrist extension

  • Asymmetric Moro reflex in infants (absent or impaired on the affected side)

  • Sensory loss in the C5 and C6 dermatomes (thumb and lateral surface of the forearm and arm)

• Treatment

  • Immobilization in flexion and external rotation with an abduction brace

  • Physiotherapy

  • Surgery for severe nerve damage or prolonged cases

• Injury to the lower trunk of the brachial plexus (C8–T1)

• Etiology

  • Hyperabduction of the arm

    • Trauma (e.g., breaking a fall by grabbing a branch)

    • Birth injury: excessive upward traction on the arm during delivery

  • Compression of the lower trunk of brachial plexus (subacute to chronic onset)

    • Pancoast tumor

    • Cervical rib

• Clinical features

  • Weakness of intrinsic hand muscles (thenar, hypothenar, lumbricals, interossei) → total claw hand (persistent flexion of the interphalangeal joints and extension of the metacarpophalangeal joints in the hand)

  • Preganglionic Horner syndrome if injury occurs proximal to the white ramus communicans

  • Decreased peripheral pulses if subclavian vessels are compressed by a Pancoast tumor or cervical rib (see “Thoracic outlet syndrome”)

  • Absent grasp reflex in infants

  • Sensory loss in the C8 and T1 dermatomes (little finger and medial surface of the forearm and arm)

• Treatment

  • Splinting the hand to correct the claw hand

  • Physiotherapy

  • Surgery for severe nerve damage