Imaging of the Wrist and Hand

, Royal Victoria Hospital, McGill University, Montrèal, Canada.

Disclosures

Medscape General Medicine. 1999;1(1) 

In This Article

Plain Radiography

Radiologic evaluation of sports injuries of the wrist and hand should commence with plain radiographs. Although plain radiography provides information in only two dimensions and cannot give detailed soft-tissue information, it is an excellent screening tool. Furthermore, plain radiography is the primary modality used in ongoing radiologic assessment of the trauma patient, primarily because it is inexpensive and easily obtained

When obtaining radiographs, a minimum of two views, taken at orthogonal angles, should be requested to provide information in three planes. By convention, posteroanterior (PA) and lateral radiographs comprise the core of radiologic evaluation of the wrist and hand (Fig. 1). At most institutions, oblique radiographs are included as part of the standard wrist and hand exam to increase sensitivity to carpal, metacarpal, and phalangeal fractures, respectively (Fig. 2). The semipronated and semisupinated (reverse) oblique views are part of the four-view wrist series and the semipronated oblique view is part of the three-view hand series. In the wrist, the semipronated oblique is useful in identifying scaphoid fractures, the most common carpal bone fracture (Fig. 3). The reverse oblique is quite useful for detecting fractures of the ulnar-sided carpal bones (Fig. 4).[1,2]

Figure 1. (a) Oblique radiograph of the left thumb demonstrating dorsal subluxation of the first metacarpal bone at the basal joint. (b) Restoration of alignment at the first carpometacarpal joint is seen on post reduction posteroanterior radiograph of the thumb. No fracture is identified.
Figure 2. Semipronated oblique radiograph of the left hand demonstrates fractures of the second, third, and fourth metacarpal bones, the proximal phalanges of the thumb and index finger, and the distal tufts of the index, long, and ring fingers.
Figure 3. Semipronated oblique radiograph of the wrist demonstrates the scaphoid waist and the scaphotrapezial joint.
Figure 4. Semisupinated (reverse) oblique radiographs of the right and left hands. Fractures of the (a) hamulus and (b) pisiform, respectively, are identified. In both cases, posteroanterior, lateral and semipronated oblique views were negative.

In evaluating standard wrist or hand radiographs, it is important to assess quality (including film technique) and positioning of the extremity. Criteria have been established for determining the quality of the lateral wrist radiograph. The lateral view should span from the distal radius to the base of the metacarpal bones. A good lateral is one in which the ventral margin of the pisiform bone lies midway between the anterior cortices of the scaphoid and capitate head.[3] This is especially important for accurate assessment of the lunate and perilunate structures. Accurate assessment of distal radial alignment in a Collesí fracture also relies on a satisfactory lateral view. Indirectly, information about the intrinsic and extrinsic carpal ligaments (dorsal and volar intercalated segment instability) can also be gained from a good lateral view.

Less stringent criteria govern the quality of the lateral radiograph of the hand. The main goal of this view is to demonstrate the digits distinctly without overlap (Fig. 5).

Figure 5. Lateral radiograph of the right hand showing spreading of the digits, hence the name "fan lateral."

To accurately and reproducibly assess carpal alignment and ulnar variance, it is necessary to have a good PA radiograph.[4,5] Carpal alignment is judged by the ability to connect the cortical margins of the bones of the proximal and distal carpal rows, also referred to as Gilula's arcs. The inability to connect the cortical margins of the carpal bones in a smooth arc suggests the presence of ligamentous instability and/or fracture. Ulnar variance refers to the position of the cortical margin of the distal ulna relative to that of the distal radius. It gives insight into the degree of axial loading transmitted to the lunate and may therefore be helpful in determining the etiology of repetitive wrist trauma (Figs. 6,7).

Figure 6. (a) Posteroanterior and (b) lateral radiographs of the distal forearm show osteosclerosis and collapse of the lunate consistent with avascular necrosis related to ulnar minus variance. A plate and screw assembly transfix the site of the healing distal radial osteotomy. This corrective procedure, resulting in neutral ulnar variance, should unload the increased stress to the lunate that was felt to result in lunatomalacia.
Figure 7. Posteroanterior view of the left hand. Minimal ulnar positive variance has resulted in radiolucency and cortical irregularity of the proximal ulnar-sided aspect of the lunate indicating ulnar impaction.

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