Anatomical Basis of Wrist Drop

Causes of Radial Nerve Injury Leading to Wrist Drop

Wrist drop, also known as radial nerve palsy, occurs due to injury or compression of the radial nerve. This nerve is responsible for the extension of the wrist and fingers. The condition results in an inability to lift the wrist and fingers, leading to functional impairment.

Anatomy of the Radial Nerve

The radial nerve arises from the brachial plexus and travels down the arm. It provides motor innervation to the extensor muscles of the forearm and sensory supply to the posterior arm, forearm, and hand.

Common Causes of Radial Nerve Injury

• Fracture of the Humerus: Midshaft humeral fractures can damage the radial nerve.
• Compression Neuropathy: Prolonged pressure on the nerve, such as in 'Saturday night palsy'.
• Surgical Trauma: Procedures involving the upper limb may inadvertently affect the radial nerve.
• Lead Poisoning: Chronic exposure to lead has been associated with radial nerve dysfunction.

Symptoms and Clinical Presentation

Patients with wrist drop exhibit:

• Inability to extend the wrist and fingers
• Weakness in grip strength
• Loss of sensation along the radial nerve distribution

Diagnosis and Treatment

Diagnosis is based on clinical examination, nerve conduction studies, and electromyography. Management includes physiotherapy, splinting, and, in severe cases, surgical nerve repair.