REIDER PART 1
47

Chapter 4

Hand and Wrist 137

Although the outlines of the individual tendons cannot bc palpated, thcy can bc fclt to glidc bcncath the exam-iner’s fingertips if this area is palpated while the patient flexes and cxtcnds his or her fingers. Palpable synovial thickening around these tendons is a common occur-rence in rheumatoid arthritis.

Continuing in the ulnar direction, moderately firm palpation allows the examiner to detect the pulsations of the ulnar artery (see Fig. 4-50B). The flexor carpi ulnaris tendon, a thick tendon along the ulnar border of the volar wrist, can be uscd as a landmark to locate the ulnar pulse. The ulnar artery lies just to the radial side of the flexor carpi ulnaris. The prominence of the flexor carpi ulnaris can be further inereased by asking the patient to ulnar-deviate the wrist and then flex it against resistance. The ulnar nerve travels deep to the ulnar artery and cannot be distinctly palpated.

As the flexor carpi ulnaris tendon is followed dis-taiły, it can bc noted to insert into an oval bony prominence, the pisiform bonę, at the basc of the hypothcnar eminence. The pisiform can be used as a landmark to locate the hook of the hamate bonę. If the examiners own thumb is placed over the pisiform, so that the inter-phalangeal flexion crease of the exa miner’s thumb lies at the proximal end of the pisiform and the tip of the exam-iners thumb is aimed toward the base of the patienfs index finger, firm palpation with the tip of the exam-iners thumb compresses a hard bony prominence corre-sponding to the hook of the hamate (Fig. 4-53). The hook of the hamate is distal and radial to the pisiform, in linę with the ring finger. The fascial structure connecting these two landmarks, the pisohamate ligamenty forms the roof of the ulnar tunnel (Guyon’s canal). The ulnar nervc and artery run through this tunnel and may become compressed there.

■ MANIPULATION

Muscle Testing

Wrist and Finger Extensors

The primary extensors of the wrist are the extensors carpi radialis longus and brevis and the extensor carpi ulnaris. Because the finger extensors cross the wrist, they also can assist in wrist extension. Wrist extensor strength is usually tested with the patienfs elbow flexed and fore-arm pronated. The patient is asked to make a fist and extend the wrist. The examiner then supports the patienfs forearm while pressing downward on the dor-sum of the patienfs hand. The patient is instructed to resist this pressure as strongly as possible (Fig. 4-54A). If normal strength is present, the examiner is unable to break the strength of the extensors or is able to break the strength only with considerablc difficulty.

The method just describcd tests the extensor carpi ulnaris, the extensor carpi radialis brevis, and the exten-sor carpi radialis longus as a group. If the examiner wishes to focus the test on the extensor carpi ulnaris, the patient is asked to extend the wrist in an ulnar-deviated position (see Fig. 4-54B). Similarly, if the examiner wishes to focus on the extensors carpi radialis longus and brevis, the patient is asked to extend the wrist in the radial-deviated position (see Fig. 4-54C). Palpation of the individual tendon in ąuestion provides supplementary verification that the tendon is indeed under tension.

The extensors carpi radialis longus and brevis are innervated by the radial nerve itself, whereas the extensor carpi ulnaris is inncrvated by the posterior interosseous branch of the radial nerve. A posterior ititerosseous nerve palsy, therefore, denervates the extensor carpi ulnaris but leaves the radial wrist extensors unaffected. In this ca.se, the

Figurę 4-53. A and B, Palpation of the hook of the hamate.