REIDER PART 1
53

Charter 4_Hand and Wrist 143

Figurę 4-65. A, Assessing thumb extensor strength. B, Assessing exton$or pollicis longus strength in isoiation.

patient to abduct thc extended thumb perpendicular to the palm. The patient is instructed to maintain this abducted position while the cxaminer tries to force the thumb hack toward the palm (Fig. 4-67). Normally, the examiner feels moderatc rcsistance before being able to force the thumb hack into the palm. Radial abduction may be tested by having the patient abduct thc thumb in the piane of the hand while the hand is lying fiat on a table.

Thumb adduction is primarily a function of the adductor pollicis, the only one of the four thenar muscles

Figurę 4-66. Assessing thumb flexion strength.

to be innervated solely by the ulnar nerve. There are two ways of testing the adductor pollicis. The first is thc rcvcrse of the test for thumb abduction strength. In this case, the examiner’s frnger is placed against the patient s hand on the pal mar aspcct of the second metacarpal. The patient is then askcd to adduct the thumb against the examiner^łs Finger. The patient is instructed to maintain the thumb in the adducted position while the examiner attempts to puli the thumb back into abduction (Fig. 4-68). In the normal patient> the examiner should feel moderate resistance before being able to overcome the patient s own adductor pollicis.

The adductor pollicis may also be tested using Froment’s test, which evaluates the strength of key pinch,

Figurę 4-67. Assessing thumb palmar abduction strength.