REIDER PART 1
33

Chapter 4 Hand and Wrist 123

Figurę 4-32. Active wrist flexion.

far as possible (Fig. 4-30). In most normal wrists, active extension is possible to 60° or 70°. When a passive force is added to the wrist, such as when an individual performs a pushup, extension may increase to 90° (Fig. 4-31). Flexion (palmar flexion) is then evaluated by asking the patient to bend the wrist downward as far as possible (Fig. 4-32). Normal flexion rangcs from about 60° to 80°.

If the patients hand is relaxed while demonstrating extension and flexion of the wrist, the tenodesis effect of the normal resting tension in the flexors and extensors of the fingers and thumb is demonstrated. When the wrist is passively extended, the flexor tendons are passively tight-ened, causing the fingers and thumb to flex (Fig. 4-33A). Differentia! tension in the flexor tendons of the fingers causes them to assumc the progressive arcade of flexion prcviously describcd. When the wrist is passively flexed, the extensor tendons are passively tightened and the flexor tendons relaxed, causing the fingers and thumb to pas-sively extend (Fig. 4-33B). Either portion of the tenodesis effect can be ovcrcome by active movement of the fingers.

Radial and Ulnar Deviation. The two remaining move-ments of the wrist are radial and ulnar deviation. The neu-tral, or 0°, position for the measurement of deviation is the point at which an imaginary linę through the long finger and third metacarpal aligns with the axis of the forearm. To assess radial deviation, the patient is asked to bend the wrist toward the radial side of the forearm (Fig. 4-34). The average amount of normal radial deviation is about 20°. Ulnar deviation is assessed by asking the patient to bend the wrist toward the ulnar side of the forearm (Fig. 4-35). Normal ulnar deviation averages about 30° to 40°. If the examiner assesses ulnar deviation with the patients forearm supinated, a mild increase in motion is noted.

Finger Motion

Evaluation of the rangę of motion of the fingers and thumb involves the assessment of many individual joints and movcmcnts. A good screening test for thumb and finger motion is to ask the patient first to make a tight fist and then to fully extend the fingers and thumb. This brief procedurę allows the examiner to pinpoint an area of potential abnormality and to focus on it in the detailed examination.

Ali joints of the fingers are capable of flexion and extension. In the assessment of flexion and extension, the ncutral position is usually considered the point at which the dorsum of the extended finger is parallel with the dor-sum of the hand.

Extension and Flexion. Extension of the DIP, the PIP, and the MCP joints is usually assessed simultancously.

Figurę 4-33. Tenodesis effect. A, Wrist extension with Finger flexion. B, Wrist ftexion with finger extension.