Nerves of hand tests are clinical examinations designed to assess the function of the major nerves that supply the hand: the median, radial, and ulnar nerves. These tests evaluate both the motor (muscle movement) and sensory (feeling) functions of each nerve to identify any potential nerve damage or dysfunction.
Understanding Hand Nerve Tests
These tests are crucial in diagnosing conditions such as nerve entrapment, injuries, or neuropathies that can lead to weakness, numbness, tingling, and pain in the hand and fingers. Each nerve has specific muscles it innervates and areas of sensation it covers, making targeted testing possible.
Specific Nerve Tests
Median Nerve Tests
- Motor Function: The primary motor test for the median nerve involves checking the thumb abduction, the movement of the thumb away from the palm. This tests the Abductor Pollicis Brevis (APB) muscle, which is innervated by the median nerve.
- Sensory Function: Sensation is assessed by checking the feeling at the radial border of the tip of the index finger. This area is supplied by the median nerve, and any altered sensation indicates potential nerve issues.
Radial Nerve Tests
- Motor Function: To assess the radial nerve's motor function, the extension at the metacarpophalangeal joints (MCPJ), where your fingers join your hand, is examined. This evaluates the Extensor Digitorum (ED) muscle, which the radial nerve controls.
Ulnar Nerve Tests
- Motor Function: The ulnar nerve is assessed by checking the ability to perform finger abduction (spreading the fingers apart) and adduction (bringing the fingers together). This tests the palmar and dorsal interossei muscles, which the ulnar nerve innervates.
Summary Table of Nerve Tests
| Nerve | Motor Test | Sensory Test |
|---|---|---|
| Median Nerve | Thumb Abduction (tests APB) | Radial border of the tip of the index finger |
| Radial Nerve | MCPJ Extension (tests ED) | Various locations on the dorsal (back) side of the hand and arm, particularly the web space between the thumb and index finger. |
| Ulnar Nerve | Finger Abduction & Adduction (tests interossei) | Sensation over the little finger and ulnar side of the ring finger |
Practical Application
- Nerve tests are often performed by physicians, physical therapists, or occupational therapists.
- The specific tests conducted may vary based on the patient's symptoms and suspected nerve involvement.
- Results help in pinpointing the affected nerve and guiding appropriate treatment.
- Abnormal results might lead to further investigations like electrodiagnostic studies (EMG/NCS).
