When you finish this chapter you will be able to:
Describe the bony, ligamentous, and muscular anatomy of the elbow, forearm, wrist, and hand.
List considerations for preventing injuries to the elbow, forearm, wrist, and hand.
Describe assessment of common elbow, forearm, wrist, and hand injuries.
Discuss the possible causes and signs of various injuries that can occur in the elbow, forearm, wrist, and hand.
Explain the procedures that can be used in caring for elbow, forearm, wrist, and hand injuries.
ANATOMY OF THE ELBOW JOINT
The elbow complex is composed of three bones: the humerus, the radius, and the ulna (Figure 19–1). The distal end of the humerus forms the medial and lateral epicondyles. The olecranon process of the ulna (see Figure 19–11) articulates with the trochlea and olecranon fossa on the posterior humerus. The radial head articulates with the capitellum of the ulna. Three separate joints collectively form the elbow complex: the humeroulnar joint, the humeroradial joint, and the radioulnar joint. Flexion and extension occur at the humeroulnar and humeroradial joints. Pronation (rotating the forearm inward) and supination (rotating the forearm outward) occur at the radioulnar joint.22
Bones and ligaments of the elbow joint (anterior view).
The ulnar (medial) collateral ligament is most important for stability to a valgus force of the elbow and extends from the medial epicondyle to the proximal ulna. The annular ligament extends from the ulna, forming a sling around the radial head and thus allowing free rotation of the radius while providing stability and preventing radial head luxation. The radial (lateral) collateral ligament, which provides stability to a varus force, extends from the lateral epicondyle and attaches primarily to the annular ligament (refer to Figure 19–1).32
The muscles of the elbow consist of the biceps brachii, the brachialis, and the brachioradialis muscles, all of which are flexors of the elbow. The brachialis is the primary elbow flexor. Extension is controlled by the triceps brachii muscle. The biceps brachii and supinator muscles allow supination of the forearm; the pronator teres, in the proximal forearm, and pronator quadratus, in the distal forearm, act as pronators (Figure 19–2) (Table 19–1).22 For additional information on movements at the elbow, see Appendix C.
(A) Anterior view. (B) Posterior view. (C) Deep pronator teres and supinator muscles (anterior view).
TABLE 19–1Muscles of the Elbow