- 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 muscles;
- 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.
