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Radial, ulnar, and median nerve palsies are common exam and clinical presentations. They are best understood by linking anatomy → muscle imbalance → characteristic posture. In practice, pattern recognition at the bedside often localises the lesion before imaging or nerve studies.
The radial nerve supplies the extensor compartment of the arm and forearm. Injury leads to unopposed flexor activity, resulting in loss of wrist and finger extension. Common mechanisms include humeral shaft fractures and prolonged compression (“Saturday night palsy”).
The ulnar nerve innervates most intrinsic hand muscles, critical for fine motor control. Loss of interossei causes finger abduction/adduction failure and a characteristic imbalance between long flexors and extensors. Lesions are common at the elbow (cubital tunnel) or wrist (Guyon’s canal).
The median nerve supplies most forearm flexors and thenar muscles. In proximal lesions, loss of finger flexion becomes apparent when the patient attempts to make a fist. Distal lesions primarily affect thumb opposition and precision grip.
Ask the patient to extend the wrist (radial), abduct/adduct fingers (ulnar), and oppose the thumb (median). Always compare both sides and consider proximal causes (cervical radiculopathy) if findings are mixed. In UK practice, document neurovascular status carefully after trauma and before/after splinting.
Radial = extension, Ulnar = intrinsic hand control, Median = precision grip. If you can picture the muscle imbalance, the diagnosis usually becomes obvious at the bedside.