Cubital Tunnel Syndrome: Clinical Findings

- Discussion:
    - note carrying angle of the elbow (for cubitus valgus);
    - r/o subluxation:
         - palpate the nerve in the cubital tunnel and note its mobility;
         - it is essential to know whether ulnar nerve subluxation is present;
    - motor findings:
         - since the ulnar nerve has more motor than sensory fibers, hence look for predominance of motor dysfunction;
         - weakness, if it occurs, may affect many functions of hand, including finger abduction, thumb abduction, pinching of thumb & 
                forefinger, power grip, and wrist flexion (FCU);
         - due to the topography of the ulnar nerve, the hand intrinsic muscles are often more severely involved than are the FCU and FDP 
         - patients may have difficulty in buttoning a shirt;
         - Froment's sign: weakness of the adductor pollicis;
                - ask patient to grasp a piece of cardboard between the index finger and thumb against resistance;
                - in pts w/ weakness of adductor pollicis, there will be flexion of IP joint of thumb because of substitution of median innervated FPL 
                      for a weak adductor pollicis;
         - grip strength is usually only 68% of the normal side (look for loss of grip dexterity);
         - intrinsic wasting is seen in less than 20% of patients with cubital tunnel syndrome;
    - tenderness:
         - local tenderness posterior to the medial epicondyle and Tinel's sign at the elbow;
         - more severe cubital tunnel syndromes will often have a more severe Tinel's sign;
    - sensory changes:
         - pts w/ ulnar-nerve compression typically note numbness in little finger & medial side of the hand;
         - pain and tenderness may occur at elbow and radiate toward hand;
         - numbness over dorsum of hand would be expected in cubital tunnel syndrome in contrast to compression within Guyon's canal
                 (where dorsal sensory numbness would not be expected;
    - elbow flexion test: (Phalen's test for cubital tunnel);
         - increase in paresthesias w/ elbow flexion is a reliable sign of ulnar entrapment;
         - this test will be positive in 89% of patients with cubital tunnel syndrome

The elbow flexion test. A clinical test for the cubital tunnel syndrome.

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, May 31, 2012 12:21 pm