REIDER PART 1
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124 Chapter4 Hand and Wrist

Figurę 4-34. A, Active radial deviation. B, Neutral.

Figurę 4-35. Active ulnar deviation.

With the forearm pronated, the patient is asked to straighten the fingers as far as possible (Fig. 4-36). It is best to have the patient extend all four fingers togethcr because tethering among the flexor tendons limits exten-sion to a varying degree if the patient attempts to extend the fingers one at a time while keeping the others flcxed. Active extension of the DIP, the PIP, and the MCP joints should be possible to at least a neutral position. Mild hyperextension is common, especially in the MCP joints. Some loose-jointed patients exhibit hyperextension at the MCP joints measuring 30° or morę. Passive exten-sion of the fingers can be measured by gently pushing the finger upward with the examiner’s own finger or thumb (Fig. 4-37). In most individual$> this leads to minimal increases in extension of the interphalangeal joints but a marked increase in extension of the MCP joint. Passive hyperextension of the MCP joint of the index finger to 70° or 80“ is not unusual. The ability to passively hyperextend the index MCP joint to 90° or morę is considered by many to be a sign of generalized ligamentous laxity.

Active flexion of the finger joints is assessed by ask-ing the patient to bend the fingers downward into a tight fist. Flexing the fingers so that the tips are pressed against the distal palmar crease allows assessment of flexion of the DIP, the PIP, and the MCP joints (Fig. 4-38A). If the fingertips are pressed against the wcb flexion crease of the fingers with the MCP joints extended, flexion of the interphalangeal joints can be assessed independent of MCP joint motion (Fig. 4—38B). Normal DIP joint flex-ion ranges from 70° to 90°. Normal PIP joint flexion is greater, averaging about 110°. Normal active MCP joint flexion also ranges from about 80° to 90°.

In addition to recording the individual flexion angles of the finger joints, an overall assessment of finger flexion can be madę by measuring the distance between the fingertips and the transverse palmar (distal palmar) crease. Normally, the fingertips should be able to touch the transverse palmar crease when a tight fist is madę. If they cannot reach it, the distance may be measured in millimeters (see Fig. 4-38C). This method is helpful for serial assessment of improvement following treatment of hand injuries.

If flexion of the interphalangeal joints of the fingers is limited, the most common causes are posttraumatic scar-

Figure 4-36. Active finger extension.