The wrist is the final link of joints that positions the hand for functional activities. It functions to control the length-tension relationship of the multiarticular muscles of the hand as they adjust to various activities. The wrist is often considered the most complex joint of the body, both from an anatomical and physiological perspective. However, there are two points of consensus regarding the wrist: (1) the structure and biomechanics of the wrist as well as the hand vary significantly from person to person and (2) even subtle variations can produce differences in the way a particular functional activity occurs.9 The hand is a valuable tool through which we control and manipulate our environment and express ideas and talents. It also has an important function of providing sensory feedback to the central nervous system.
This chapter is divided into three major sections. The first section briefly reviews the rather complex structure and function of the wrist and hand—information that is important to know in order to effectively treat patients with wrist and hand pathology. The second section describes common disorders and guidelines for conservative and postoperative management. The last section describes exercise techniques commonly used to meet the goals of treatment during the stages of tissue healing and phases of rehabilitation.
Structure and Function of the Wrist and Hand
The bones of the wrist include the distal radius and ulna. The scaphoid (S), lunate (L), triquetrum (Tri), and pisiform (P) make up the proximal carpal row; the trapezium (Tm), trapezoid (Tz), capitate (C), and hamate (H) make up the distal carpal row. Five metacarpals and 14 phalanges make up the hand and the five digits (Fig. 19.1).
Bones of the wrist and hand complex.
Joints of the Wrist and Hand
Wrist Joint: Characteristics and Arthrokinematics
The distal radioulnar (RU) joint is not considered part of the wrist joint, although pain and impairments in this forearm articulation are often described by the patient as wrist pain. Structure and function of the RU joints are described in Chapter 18.
The wrist joint is multiarticular and is made up of two compound joints, the radiocarpal/ulnocarpal and midcarpal joints. It is biaxial, allowing flexion, extension, radial deviation, and ulnar deviation. However, due to an oblique axis of rotation, most activities are carried out with an oblique wrist motion from extension with radial deviation to flexion with ulnar deviation. This oblique plane of motions is referred to as the "dart thrower's motion" (DRT) and is an important concept when developing treatment plans for individuals with wrist pathology.24,53 Stability is provided by numerous extrinsic ligaments: the ulnar and radial collateral, the dorsal and volar (palmar) radiocarpal, the ulnocarpal and ...