Cubital Tunnel Syndrome

Procedure

With the elbow slightly flexed, roll the ulnar nerve gently under the fingers where it runs behind the medial epicondyle. Compare its calibre with the same nerve on the other arm.

Positive Finding

The nerve feels thicker or more prominent than on the unaffected side.

Sensitivity / Specificity

Reference: Beekman R, Schreuder AHCML, Rozeman CA, Koehler PJ, Uitdehaag BMJ. The diagnostic value of provocative clinical tests in ulnar neuropathy at the elbow is marginal. J Neurol Neurosurg Psychiatry. 2009;80:1369-74.

Interpretation

Rarely positive, but meaningful when it is. This finding appears in only 28% of confirmed cases, so a normal-feeling nerve rules nothing out — yet it correctly clears 87% of people who do not have the condition (PMID 19553231), making it one of the more useful positive findings at the elbow. This figure comes from a study that compared patients against OTHER patients presenting with elbow symptoms, rather than against healthy volunteers. That is the harder and more clinically realistic comparison, which is why the numbers look modest.

Procedure

Percuss or tap gently over the ulnar nerve as it passes behind the medial epicondyle of the humerus. Assess for reproduction of tingling or pain radiating distally into the ring and little fingers.

Positive Finding

Sharp pain or tingling (paresthesia) in the distribution of the ulnar nerve (ring and little fingers) with percussion

Sensitivity / Specificity

Reference: Beekman R, Schreuder AHCML, Rozeman CA, Koehler PJ, Uitdehaag BMJ. The diagnostic value of provocative clinical tests in ulnar neuropathy at the elbow is marginal. J Neurol Neurosurg Psychiatry. 2009;80:1369-74.

Interpretation

Tapping over the ulnar nerve provokes symptoms in the nerve it irritates. Against other patients presenting with elbow symptoms, this test detects about 62% of cases and correctly clears about 53% of those without it (PMID 19553231) — so a positive result is close to a coin toss and a negative one misses about a third of cases. Older figures put specificity as high as 99%, but those compared patients against healthy volunteers, which makes any test look far better than it performs in clinic. Use it as one piece of a picture, never on its own.

Procedure

Apply gentle pressure along the ulnar nerve behind the medial epicondyle and note whether it is tender compared with the other side.

Positive Finding

Local tenderness over the ulnar nerve at the elbow.

Sensitivity / Specificity

Reference: Beekman R, Schreuder AHCML, Rozeman CA, Koehler PJ, Uitdehaag BMJ. The diagnostic value of provocative clinical tests in ulnar neuropathy at the elbow is marginal. J Neurol Neurosurg Psychiatry. 2009;80:1369-74.

Interpretation

Present in about a third of confirmed cases (32%) and correctly clears 80% of those without the condition (PMID 19553231). Like nerve thickening, it is a low-yield but reasonably trustworthy finding: worth noting when present, meaningless when absent. This figure comes from a study that compared patients against OTHER patients presenting with elbow symptoms, rather than against healthy volunteers. That is the harder and more clinically realistic comparison, which is why the numbers look modest.

Procedure

Patient fully flexes both elbows and holds the position with palms facing away for 60 seconds. Observe for reproduction of symptoms in the ulnar nerve distribution.

Positive Finding

Reproduction of paresthesia or pain in the ring and little fingers within 60 seconds

Interpretation

Sustained elbow flexion compresses the ulnar nerve in the cubital tunnel; positive result suggests mechanically significant compression and supports diagnosis This maneuver is sustained elbow flexion; it is not Phalen's test, which is a wrist test. The published figures for cubital tunnel (61% sensitivity, 40% specificity, PMID 19553231) belong to a combined flexion-AND-compression maneuver, not to sustained flexion alone, so they are not shown here.

Procedure

Patient's elbow is flexed 90°. Examiner applies direct, gentle pressure over the cubital tunnel (behind medial epicondyle) for 30–60 seconds. Assess for paresthesia in the ulnar nerve distribution.

Positive Finding

Reproduction of tingling, numbness, or pain in the ring and little fingers with maintained pressure

Interpretation

Direct pressure over the compressed site reproduces symptoms; supports localization of nerve compression at the cubital tunnel level The reference previously cited here appeared on five of the six tests for this condition, including an electrodiagnostic investigation, and could not be confirmed to exist. It has been removed rather than left in place.

Procedure

Electrodiagnostic testing measuring nerve conduction velocity across the elbow and electromyographic activity of ulnar-innervated muscles. Formal testing performed by neurophysiologist or trained clinician.

Positive Finding

Slowing of nerve conduction velocity across the elbow segment (>10 m/s difference compared to forearm), reduced compound muscle action potential amplitude, or denervation on EMG

Interpretation

Gold standard for confirming ulnar nerve compression and assessing severity; helps differentiate cubital tunnel syndrome from other causes of ulnar neuropathy The reference previously cited here appeared on five of the six tests for this condition, including an electrodiagnostic investigation, and could not be confirmed to exist. It has been removed rather than left in place.

Procedure

Patient is asked to grasp a sheet of paper between thumb and index finger on each hand while examiner attempts to withdraw the paper. Observe for flexion of the interphalangeal joint of the thumb, indicating weakness of thumb adduction.

Positive Finding

Excessive flexion at the thumb interphalangeal joint on the affected side (compensation for adductor pollicis weakness)

Interpretation

Indicates significant ulnar nerve motor involvement and intrinsic hand muscle weakness; suggests advanced or moderately severe compression The reference previously cited here appeared on five of the six tests for this condition, including an electrodiagnostic investigation, and could not be confirmed to exist. It has been removed rather than left in place.

Procedure

Using a calibrated two-point discriminator, assess the smallest distance at which the patient can distinguish two simultaneous points applied to the fingertips of the ring and little fingers. Compare with unaffected side.

Positive Finding

Increased two-point discrimination distance (>6 mm in digits innervated by ulnar nerve, compared to <3 mm contralaterally)

Interpretation

A late sign. Two-point discrimination stays normal until nerve compression is well advanced, so a normal result does not reassure. It is more useful for tracking change over time than for making the diagnosis, and it cannot distinguish what is happening inside the nerve.

Procedure

Patient sits with the elbows tucked at the sides, flexed to 90°, and resists the examiner pushing the forearms inward (resisted shoulder external rotation). The examiner then lightly scratches the skin over the cubital tunnel and immediately repeats the resisted test.

Positive Finding

A brief loss of resistance on the scratched side — the arm gives way momentarily.

Sensitivity / Specificity

Related reference: Cheng CJ, Mackinnon-Patterson B, Beck JL, Mackinnon SE. Scratch collapse test for evaluation of carpal and cubital tunnel syndrome. J Hand Surg Am. 2008;33(9):1518-24.

Interpretation

Detects about 69% of cases of cubital tunnel syndrome (PMID 18984333). Its specificity is not shown here: the study compared patients against healthy volunteers rather than against other people with elbow symptoms, which inflates specificity considerably. This test appeared on the golfer’s elbow page in earlier versions of this site; it was studied for nerve compression, not for medial epicondylalgia, and belongs here.