The Hand and Wrist
Figures 5.1–5.3 illustrates the surface anatomy of the proximal wrist. The wrist is composed of distal radius and ulna, which articulate with each other to form the radioulnar joint. The distal radius also articulates with the scaphoid and lunate bones [1
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The Hand and Wrist James M. Daniels and Bill Shinavier
Anatomy and Function Figures 5.1–5.3 illustrates the surface anatomy of the proximal wrist. The wrist is composed of distal radius and ulna, which articulate with each other to form the radioulnar joint. The distal radius also articulates with the scaphoid and lunate bones [1]. The distal ulna articulates with the triangular fibrocartilage complex (TFCC), which functions much like the meniscus of the knee. The TFCC also has ligamentous attachments to the lunate, capitate, and triquetrum [1]. The distal wrist is composed of the eight carpal bones arranged in two rows. The proximal carpals (scaphoid, lunate, triquetrum, and pisiform) are closely approximated to the radius, while the distal carpals (trapezium, trapezoid, capitate, and hamate) are closely associated with the metacarpal bones. When the wrist deviates radially or dorsiflexes, the scaphoid flexes palmarly, which puts it in a precarious position to be injured when a patient falls, particularly when the patient falls on an outstretched hand [2]. Figure 5.4 shows the basic anatomy of the wrist.
J.M. Daniels (*) Professor, Department of Family and Community Medicine, Director, SIU Primary Care Sports Medicine Fellowship, SIU School of Medicine, Quincy, IL 62794, USA e-mail: [email protected] J.M. Daniels and M.R. Hoffman (eds.), Common Musculoskeletal Problems: A Handbook, DOI 10.1007/978-1-4419-5523-4_5, © Springer Science+Business Media, LLC 2010
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J.M. Daniels and B. Shinavier
Fig. 5.1 Surface anatomy of the hand – palmar aspect
Each of the digits has two neurovascular bundles, one on the radial side and the other on the ulnar side, which contain an artery, vein, and nerve [3]. The extensor tendons, which originate on the lateral dorsal forearm, insert on the dorsal hand. The flexor tendons from the medial forearm insert on the palm of the wrist and hand [4]. The superficial flexor tendon on each phalynx inserts at the base of the middle phalynx, while the deep flexor tendon inserts on the base of the distal phalynx. Figure 5.5 shows the extensor and flexor tendons of the fingers. The metacarpal–phalangeal (MCP) joint of the thumb differs from the usual “ball and socket” joints of the other digits. Instead, it is a “saddle” joint, which allows for the pincer grip. This joint is largely supported by soft tissue and is therefore easily injured.
5 The Hand and Wrist
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Fig. 5.2 Surface anatomy of the hand – dorsal aspect
Red Flags Several hand and wrist conditions should be urgently investigated or referred due to potential serious sequelae. 1. Compound fracture. Any compound fracture should be urgently referred to a specialist. Active or profuse bleeding should be controlled with pressure; no attempts at exploration should be made. 2. “Fight bite.” A fight bite occurs when the fist strikes a tooth of another person, usually over the knuckles of the ring or little fingers. This type of injury carries high risk of penetration of tendon or even bone, and even a very small mark on
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