I’ve mentioned my wrist pain in a previous email on wrist clunk. Triggers: typing and using a keyboard (laptop or desktop). Relieved by: partying and chilling and enjoying life, my friend.
What I learned today
I usually have elbow pain that accompanies my wrist pain (yay me). Cubital tunnel syndrome is on the differential. So, might as well learn about diagnosing it, right?
Symptoms
Altered sensation of the little and ring fingers, worsened by prolonged elbow flexion
May report hand weakness, loss of fine coordination (e.g. difficulty clipping fingernails)
Occasionally, pain along the ulnar nerve course
→ Q: Where is muscle atrophy most readily appreciated?
1st dorsal interosseous muscle (provides bulk in the first webspace)
Signs
I recommend trying to quiz yourself on each one before reading the description.
Wartenberg sign — lack of active adduction of little finger due to weak 3rd palmar interosseous muscle => unopposed abduction from ulnar insertion of extensor digiti quinti
Froment sign — attempting a “key pinch” leads to obligate thumb interphalangeal joint flexion as the FPL tries to compensate for a weak adductor pollicis
Jeanne sign — attempting a “key pinch” leads to hyperextension of the MCP joint from the EPL (with some thumb adduction, again, due to a weak adductor pollicis)
Claw hand deformity — probably the one you learned for Step 1; seen in advanced ulnar neuropathy with the loss of lumbrical and interosseous muscles, intact extrinsic flexors, and passive hyperextension of the MCP joints with the wrist in neutral position
Testing
Sensory testing — 2-point discrimination, vibration, Semmes-Weinstein monofilament
Nerve percussion at retrocondylar groove
Elbow flexion test — hold the elbow in full flexion with the wrist extended; positive test if paresthesias and pain follow
Flexion-compression test — manual compression of the ulnar nerve posterior to the medial epicondyle during elbow flexion
Scratch collapse test — “Examiner lightly scratches a patient’s skin over the presumed area of nerve compression while the patient sustains resisted external rotation. Allodynia caused by compression neuropathy is thought to impart a brief loss of muscle resistance after the stimulation, resulting in the subsequent collapse of the extremity under resistance.”
In this JAAOS review (see below), the authors mention that they don’t rely on the scratch collapse test for diagnosis. Neither did the attending who evaluated me.
Lastly, you can test for ulnar nerve stability by placing a finger posterior to the medial epicondyle while flexing the elbow. It may subluxate, perch, or remain stable.
However, up to 37% of adults may have ulnar nerve hypermobility.1 It's not necessarily associated with symptomatic cubital tunnel syndrome. But being aware of a hypermobile nerve may lead you to consider another treatment besides in situ decompression.
Sources
Staples, J. R. & Calfee, R. Cubital Tunnel Syndrome. J Am Acad Orthop Sur25, e215–e224 (2017).
Calfee RP, Manske PR, Gelberman RH,Van Steyn MO, Steffen J, Goldfarb CA:Clinical assessment of the ulnar nerve at theelbow: Reliability of instability testing andthe association of hypermobility withclinical symptoms.J Bone Joint Surg Am2010;92(17):2801-2808.