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148 Chapter4 Hand and Wrist

Figurę 4-75. A, Phalen’s test. B, Reverse Phalens test.

that connects the pisiform with the hook of the hamate. Through this canal run the ulnar artery and ncrve. The most sensitive test for ulnar nerve entrapment at Guyon’s canal is the ulnar nerve compression test of the wrist. Analogous to the carpal tunnel compression test, the examiner performs it by compressing the ulnar nerve just radial and proximal to the pisiform bonę for 1 minutę (Fig. 4-76). If this produces tingling or numbness in the distribution of the ulnar nerve, it is evidence for ulnar nerve compression at Guyons canal. TinePs test can also be used to screen for ulnar nerve compression at this site. In this case, the examiner supports the supinated hand and taps with the tip of the opposite long finger ovcr the ulnar nerve (Fig. 4-77).

Stability Tfsting

Interphalangeal Joints. The collateral ligaments of the interphalangcal joints of the thumb and fingers are tested in a manner analogous to that used for testing the collateral ligaments of the knee. The DIP and PIP joints of the fingers and the interphalangeal joint of the thumb are

all tested in the same fashion. Of these joints, the PIP joints of the fingers are the most likely to suffer damage to the collateral ligaments.

To test the ulnar collateral ligament of the PIP joint of the index finger, for example, the proximal phalanx of the finger to be tested is stabilized between the thumb and the index finger of the examiner’s own hand. The thumb and indcx finger of the examiner’s other hand are then used to grasp the middle phalanx of the same finger. Whilc maintaining the position of the interphalangeal joint at 30° of flexion, the examiner attempts to deviate the distal portion of the finger in the direction of the patient s thumb. This maneuver puts the ulnar collateral ligament under tension (Fig. 4-78A).

In a normal finger, virtually no movement is felt between the middle and the proximal phalanges at the PIP joint when this stress is applied. If a mild sprain of the ulnar collateral ligament is present, this stress produces pain on the ulnar side of the joint but the stability

Figurę 4-76. Ulnar nerve compression test at the wrist.

Figurę 4-77. TinePs test of the ulnar nerve at the wrist.