Wartenberg's syndrome

It is an entrapment neuropathy of the superficial radial nerve (SRN), which is a pure sensory nerve.
Also known as "cheiralgia paraesthetica".
Due to compression by the relative motion of brachioradialis and extensor carpi radialis longus (ECRL) during forearm rotation.
The nerve may be entrapped at its exit point to the subcutaneous plane by the intervening fascia.

Pure sensory nerve
Radial nerve bifurcates in the proximal forearm to give rise to SRN and posterior interosseous nerve (PIN)
SRN travels deep to the brachioradialis and lies on the undersurface of the muscle
It emerges between brachioradialis and ECRL in the distal third forearm, to become superficial (under the skin)
It bifurcates further proximal to the wrist:
- Dorsal branch to supply the 1st (autonomous dermatome) and 2nd web spaces
- Palmar branch to supply dorsoradial thumb

Symptoms

Vague pain over the dorsoradial hand
Paraesthesia (tingling sensation)
Numbness
Onset may have been precipitated by:
- tight bracelet, wrist watch, wrist band
- minor trauma to the wrist
- repetitive wrist flexion, ulnar deviation or forearm rotation

Signs

A positive Tinel's sign over the SRN at the entrapment spot is the most reliable sign
A provocative test with repeated wrist flexion, ulnar deviation and pronation (akin to Traction Tinel's sign)

Nerve conduction studies can be performed however it may be normal
Diagnostic local anaesthetic injection is the most useful test:
- Injection of 1-2ml of fast-acting local anaesthetic (1 or 2% lidocaine) at the Tinel's spot followed by resolution of the above symptoms is regarded as a positive test for nerve entrapment. Should the symptoms return predictably as the local anaesthetic wears off (after 4 hours), that is taken as a further level of confirmation.

Nonoperative

Operative

Locations