UPPER LIMB: BRACHIAL PLEXUS LESION

UPPER (C5 AND C6) BRACHIAL PLEXUS LESION: ERB-DUCHENNE PALSY (WAITER’S TIP SYNDROME)

• Usually occurs when the head and shoulder are forcibly separated (e.g., accident or birth injury or herniation of disk)
• Trauma will damage C5 and C6 spinal nerves (roots) of the upper trunk.
• Primarily affects the axillary, suprascapular, and musculocutaneous nerves with the loss of intrinsic muscles of the shoulder and muscles of the anterior arm.
• Arm is medially rotated and adducted at the shoulder: Loss of axillary and suprascapular nerves.
• The unopposed latissimus dorsi and pectoralis major muscles pull the limb into adduction and medial rotation at the shoulder.
• The forearm is extended and pronated: loss of musculocutaneous nerve.
• Sign is “waiter‟s tip.”
• Sensory loss on lateral forearm to base of thumb: loss of musculocutaneous nerve.

LOWER (C8 AND T1) BRACHIAL PLEXUS LESION: KLUMPKE’S PARALYSIS

• Usually occurs when the upper limb is forcefully abducted above the head (e.g., grabbing an object when falling, thoracic outlet syndrome or birth injury)
• Trauma will injure the C8 and T1 spinal nerve roots of inferior trunk.
• Primarily affects the ulnar nerve and the intrinsic muscles of the hand with a weakness of the median innervated muscles of the hand.
• Sign is combination of “claw hand” and “ape hand” (median nerve).
• May include a Horner syndrome.
• Sensory loss on medial forearm and medial 1½ digits.

RADIAL NERVE

• Axilla: (Saturday night palsy or using crutches)
  • Loss of extension at the elbow, wrist and MP joints
  • Weakened supination
  • Sensory loss on posterior arm, forearm, and dorsum of thumb
  • Distal sign is “wrist drop.”
• Mid-shaft of humerus at radial groove or lateral elbow (lateral epicondyle or radial head dislocation)
  • Loss of forearm extensors of the wrist and MP joints
  • Weakened supination
  • Sensory loss on the posterior forearm and dorsum of thumb
  • Distal sign is “wrist drop.”
  • Lesions of radial nerve distal to axilla, elbow extension are spared.