The wrist

Abstract

The wrist is a condyloid joint, that is to say one that allows flexion, extension, abduction, adduction and circumduction, which is a combination of the previous four movements. The proximal face of the wrist joint comprises the distal end of the radius and the articular disc of the inferior radioulnar joint (which covers the head and the ulna and is attached to the ulnar styloid process). The distal face of the wrist joint comprises the proximal articular surfaces of the scaphoid, lunate and triquetral bones in the carpus. Consideration of wrist joint movement also requires consideration of adjacent joints. The radius and ulna articulate just proximal to the wrist joint at the inferior radio-ulnar joint. Distally, the bones of the carpus articulate such that the three proximal carpal bones that constitute the distal face of the wrist joint articulate at the mid-carpal joint with other carpal bones. Flexion and extension of the wrist joint may thus be increased by associated sliding movements of the intercarpal joints, making the range of flexion appear greater than that of extension, though at the wrist joint alone flexion is actually less than extension. Because of the greater distal projection of the radial styloid, the range of abduction at the wrist is considerably less than the range of adduction. There have been only a small number of previous studies on the range of movement at the wrist joint. In the analysis of range of movement at joints certain physical and epidemiological features apply and the wrist joint is no exception. 1. Movement may occur at more than one joint. This is particularly relevant to the carpus, which moves in flexion/extension with the wrist. For the purposes of this study supination/pronation was classified as elbow movement and will not be considered further in this chapter. 2. There is divergence in the literature on the relative range of movement in dominant and non-dominant hands. Allander et al (1974) found movement at the wrist to be reduced on the dominant side, perhaps because of increased muscle tone. However, for studies at the finger joint the relationship appears to vary according to the population under study. 3. A wider range of movement may be found in female joints and this may be related both to pregnancy and the stage of the menstrual cycle at which measurements are taken. 4. The differences between active and passive movement cause a big problem. The passive range is always larger than the active range, even when the active range of movement has been deliberately enhanced by active training. If passive movement is to be measured, a strict analysis would require the force to which the joint is subjected to achieve this range of movement to be accurately quantified for each arc of movement studied. For the purposes of this study passive movement was recorded in addition to active movement, even though this is to a large extent determined by observer enthusiasm. The joint was moved to a limit just short of the threshold of pain and the movement recorded immediately; it was not subsequently corrected for the stretching effect that allows further excursion of movement after the joint has been held at the extremity of its range for a few seconds. In practice, the difference between active and passive range of movement is less of a problem at the wrist (where range is largely determined by the shape of bony prominences) than it is at ball-and-socket joints such as the hip (where range of movement is largely determined by muscle tone). ).