The wrist is the final link of joints that positions the hand for functional activities. It has the significant function of controlling the length-tension relationship of the multiarticular muscles of the hand as they adjust to various activities and grips.6 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 hand problems. 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, scaphoid (S), lunate (L), triquetrum (Tri), pisiform (P), trapezium (Tm), trapezoid (Tz), capitate (C), and hamate (H). 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 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. It is biaxial, allowing flexion (volar flexion), extension (dorsiflexion), radial deviation (abduction), and ulnar deviation (adduction). Stability is provided by numerous ligaments: the ulnar and radial collateral, the dorsal and volar (palmar) radiocarpal, the ulnocarpal, and the intercarpal.
The pisiform is categorized as a carpal and aligned volar to the triquetrum in the proximal row of carpals. It is not part of the wrist joint per se but functions as a sesamoid bone in the flexor carpi ulnaris tendon.
Characteristics. The radiocarpal (RC) joint is enclosed in a loose but strong capsule that is reinforced by the ligaments shared with the midcarpal joint. The biconcave articulating surface is the distal end of the radius and radioulnar disk (discus articularis); it is angled slightly volarward and ulnarward. The biconvex articulating surface is the combined proximal surface of the scaphoid, lunate, and triquetrum. The triquetrum primarily articulates with the disk. These three carpals are bound together with numerous interosseous ligaments.
Arthrokinematics. With motions ...