Figure 229: The Carpal Tunnel. OpenStax College, CC BY 3.0.
Clinical features
Sensory: Intermittent paraesthesia, sensory changes, or neuropathic pain in the distribution of the median nerve (lateral 2/3 palm and lateral 3.5 fingers, thenar eminence).
Motor: Reduced grip strength or loss of dexterity
Symptoms are often worse during the night, often disturbing sleep
Patients may shake their hands to relieve the pain
Examination:
Phalen’s test - wrist flexion causes symptoms
Tinel’s test - taping over median nerve reproduces symptoms
Wasting of thenar muscles, weakness and sensory changes as above
Figure 230: Thenar wasting in a patient with untreated carpal tunnel syndrome.
Investigations
CTS is a clinical diagnosis, but nerve conduction studies can be performed for confirmation.
Management
Mild-moderate symptoms - try the following:
Wrist splint
Corticosteroid injection into the carpal tunnel
If symptoms are severe or persistent despite the above, refer for specialist management:
Nerve conduction studies
Carpal tunnel decompression surgery
Cubital Tunnel Syndrome
Pathophysiology
Compression of the ulnar nerve in the cubital tunnel (between the medial epicondyle of the humerus to the olecranon process of the ulna).
Clinical features
Pain around the medial elbow, or in the forearm.
Sensory: Intermittent paraesthesia, sensory changes, or neuropathic pain in the distribution of the ulnar nerve (medial 1/3rd hand, hypothenar eminence, medial 1.5 fingers)
Atrophy of the intrinsic muscles of the hand, claw hand may be present
Positive elbow flexion test, or pressure provocative test. Tinel’s positive taping at the cubital tunnel.
Figure 231: The ulnar tunnel - a site of entrapment ulnar neuropathy. InjuryMap, CC BY-SA 4.0.
Radial Tunnel Syndrome
Pathophysiology
Compression of the posterior interosseous nerve (deep branch of the radial nerve)
Clinical features
Vague pain at the top of the forearm, which is worst a few cm proximal to the lateral epicondyle, may radiate down to the wrist
Pain is worse on pronation of the forearm
Pain is often more severe at night, disturbing sleep
On examination, extension of the thumb and index finger against resistance may replicate pain
