REIDER PART 1
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Chapter 4__Hand and Wrist

Figurę 4-57. Assessing overall finger flexor strcngth.

of flexor profundus strength in thc ring finger and the lit-tle finger, while flexor profundus function of the index finger and the long finger remains intact. Isolatcd loss of flexor profundus function to the ring finger alone, on the other hand, may be duc to avulsion of the flexor profundus slip to that digit, the condition known as jersey finger.

To test the flexor digitorum superficialis function in isolation, the patient is instructed to flex the fingers one at a time while thc examiner holds the other three fingers in fuli cxtension at all joints (Fig. 4-59). Because the flexor profundus tendons are tethered together proxi-mally, holding the other three fingers in extension inca-pacitates the flexor profundus of the finger being tested. The flexor superficialis acts alone, thus only the PIP joint and the MCP joint of the tested finger are flexed. If the flexor digitorum superficialis tendon of a givcn finger has been lacerated, the patient is unable to flex that finger when the other three are held in extension. Bccause the

Figurę 4-59. Assessing flexor digitorum superficialis function to thc ring finger.

flexor digitorum profundus to the index finger is not tethered, this test is less rcliable for the index finger. All portions of the flexor digitorum superficialis are inner-vated by the median nerve.

Radial and Ulnar Deviators of the Wrist Radial and ulnar deviation of the wrist are powered pri-marily by muscles already mentioned. The primary motors for ulnar dcviation are the exten$or carpi ulnaris and the flexor carpi ulnaris, whereas the primary motors for radial deviation are the flexor carpi radialis, the exten-sors carpi radialis longus and brevis, and the abductor

Figurę 4-58. Assessing flexor digitorum profundus. A, To the index finger. B, To thc little finger.