REIDER PART 1
45

Chaptkk 4

Hand and Wrist 135

Infections. As already mentioned, closed-space infec-tions tend to occur on the volar surface of the fingers and palm. If swelling or erythema is noted in any of the fol-lowing locations, the surface should be palpated very gen-tly for associated tenderness: the volar fingertip (felon), the volar surface over the middlc and proximal phalanges (flexor tendon sheath infectioń)> the middle and distal por-tions of the palm (midpalmar space infecłion), and the thenar eminence (thenar space infectioń). These closed-space infections can be extremely tender, so initial palpa-tion should be very gentle.

Sweating. \Vhile palpating the volar surfaces of the hand, the examiner should notę that the skin is slightly moist. This moisture increases function and improves grip. In the presence of a nerve injury such as a median, ulnar, or digital nerve laceration, the skin in the sensory distribution of the injured nerve should feel dry, hence slick, owing to loss of normal neuroregulation of sweating. This slickness can be detectcd by passing a plastic pen or pencil along one side of the digital tip with a moderate amount of pressure. If it glides as if on silk or satin then the nerve is probably cut. Normally, the exam-iner should feel a noticeable frictional drag on the instrument.

Masses. Ganglia of the flexor tendon sheath usually occur at the level of the web flexion creases of the fingers. The examiner should remember that these creases are located at about the midpoint of the proximal phalanx. A flexor sheath ganglion is rarely visible, but it can usually be palpated as a firm round nodule 3 mm to 5 mm in diameter located centrally or to one side of the flexor tendon of a finger. Flexor tendon ganglions can be transillu-minated. These ganglia can cause pain by compressing the digital nerve when an object is grasped. A giant celi tumor is a less comnion cause of a mass in the finger. It tends to occur between the joints and is firmer and larger than a ganglion. These tumors usually do not transillu-minate.

Further proximally, at the level of the transversc flcx-ion crease of the palm or the proximal flexion crease of the thumb, the examiner can palpate the nodular swelling usually associated with trigger finger. In trigger finger, the flexor digitorum superficialis tendon tends to catch in a constriction caused by thickening of the first (A-1) pul-ley that normally prevents the flexor tendons from bow-stringing. To palpate a trigger finger, the examiner presses gently over the volar aspect of the involved flexor tendon at the level of the MCP joint. The patient is asked to make a tight fist around the examiner s finger, with the exam-iner s finger tip palpating the A-l pulley at the distal pal-mar crease. The examiner should feel a nodule at the A-l pulley. The patient is asked to extend the other fingers fully, then extend the finger in question (Fig. 4-51). In the presence of trigger finger, the examiner feels a pop or snap as the involved finger extends. This is caused by the involved tendon catching at the constricted pulley. Flexor sheath ganglia may also occur in this location and be pal-pable near or over the tendon as a nodule, but no snap-ping will occur.

Eminences. In the palm of the hand, the thenar and hypothenar eminences can also be palpated for muscle tonę and bulk. If the thenar eminence is palpated while the patient is pressing the tips of the thumb and the ring finger firmly together, the muscle should feel rock hard. A softened thenar eminence is usually caused by median nerve neuropathy or basilar joint arthritis. The thenar eminence appears wasted and flaccid in advanced cases of median nerve neuropathy, whereas ulnar nerve neuropathy can lead to atrophy of the hypothenar eminence.

Wrist

The volar aspect of the wrist is palpated with the patient s elbow flexed and forearm supinated. The tendons of the first dorsal compartment are actually situated quite volarly and form the radial border of the volar aspect of the wrist (see Fig. 4-20). Just to the ulnar side of these tendons is a soft spot. Gentle palpation in this soft spot allows the examincr to detect the pulsations of the radial artery (Fig. 4-52A). Just distal to the distal flexion crease of the wrist, in linę with the radial pulse, the examiner feels a firm resistance corresponding to the tubercle of the scaphoid. Continuing distally in linę with the scaphoid, the examiner can palpate the volar aspect of the trape-zium and then the basilar joint. This area provides another site at which the tenderness associated with basilar joint arthritis can be sought.

As the examiner continucs to palpate in the ulnar direction from the radial artery, the next distinct struc-ture is the linear mass of the flexor carpi radialis tendon. This tendon is often visible and can be madę even morę prominent by asking the patient to flcx the wrist against resistance (see Fig. 4-20). The flexor carpi radialis inserts at the base of the second metacarpal. Continuing in the ulnar direction, the examincr next encounters the most supcrficial tendon of the volar wrist, the palmaris longus. The prominencc of the palmaris longus can be inereased by asking the patient to pinch the tips of the thumb and the little finger together with the wrist slightly flexed (see Fig. 4-20). The palmaris longus, which inserts into the palmar fascia at the base of the palm, exists in only about 80% of individuals and is not always bilateral.

The narrow depression between the flexor carpi radialis and the palmaris longus tendons indicates the location of the median nerve. The nerve itself cannot be distinguished by palpation. Specific tests to identify median nerve compression at the wrist, a condition known as carpal tunnel syndrome, are describcd later in this chapter.

If the examiner palpates distally along the palmaris longus tendon, the soft tissues of the wrist are felt to grow firmer as the palpating finger reaches the distal wrist