Ulnar Neuropathy: 6 Clinical Manifestations (Weakness, Claw Hand, Froment's/Wartenberg's Signs) and Treatment Options

The ulnar nerve (C8–T1) is vulnerable at the cubital tunnel (elbow) and Guyon's canal (wrist). Damage causes:

1. Motor Weakness: Thenar wasting (spared), hypothenar wasting, interossei/lumbricals 3&4 weakness → impaired finger abduction/adduction, thumb adduction (Froment's sign).
2. Sensory Loss: Medial 1.5 digits (little, ulnar half of ring) + corresponding palm/dorsum.
3. Claw Hand (Main en griffe): Hyperextension at MCP, flexion at PIP/DIP of 4th/5th digits (unopposed FDP/FDS vs. paralyzed intrinsics).
4. Functional Impairment: Difficulty with pinch, grip, fine motor (writing, buttons, jars).
5. Froment's Sign: Compensatory FPL activation (median nerve) when holding paper between thumb/index → IP flexion.
6. Wartenberg's Sign: Abducted little finger (unopposed extensor digiti minimi) due to paralyzed interossei.

Treatment

• Conservative: Night splinting (30° elbow flexion), activity modification, NSAIDs, nerve glides.
• Surgical: Cubital tunnel release ± anterior transposition (subcutaneous, submuscular); Guyon's canal decompression.

Early EMG/NCS guides prognosis. Chronic compression → irreversible axonal loss.