Chapter 23: The Elbow

William E. Prentice

OBJECTIVES

When you finish this chapter you should be able to

• Recall the structural and functional anatomy of the elbow, and relate it to overuse and traumatic injuries.

• Explain the process for assessing the injured elbow.

• Demonstrate proper immediate and follow-up management of elbow injuries.

• Devise appropriate rehabilitation techniques that can be used following injury to the elbow.

ANATOMY OF THE ELBOW JOINT

Bones

The elbow joint is composed of three bones: the humerus, the radius, and the ulna (Figure 23–1). The distal end of the humerus forms two articulating condyles. The lateral condyle is the capitulum, and the medial condyle is the trochlea. The convex capitulum articulates with the concave head of the radius. The trochlea, which is spool-shaped, fits into an articulating groove, the semilunar notch, which is provided by the ulna between the olecranon and coronoid processes. Above each condyle is a projection called the epicondyle. The structural design of the elbow joint permits flexion and extension through the articulation of the trochlea with the trochlear notch of the ulna. Forearm pronation and supination are made possible because the head of the radius rotates against the capitulum freely without any bone limitations.²⁷

Articulations

The elbow complex consists of three separate joints: the humeroulnar joint, the humeroradial joint, and the proximal radioulnar joint (Figure 23–2). The humeroulnar joint is the articulation between the distal humerus medially and the proximal ulna. When the elbow is in flexion, the ulna slides forward until the coronoid process of the ulna stops in the floor of the coronoid fossa of the humerus. In extension, the ulna slides backward until the olecranon process of the ulna makes contact with the olecranon fossa of the humerus posteriorly.⁵⁰ The humeroradial joint is the articulation of the lateral distal humerus and the capitulum. In flexion, the radius is in contact with the radial fossa of the distal humerus. The radiocapitellar joint narrows with elbow valgus and forearm pronation. In full flexion, the radial head comes in contact with the radial fossa of the distal humerus.⁵⁰ The proximal radioulnar joint is the articulation between the radial notch of the proximal lateral aspect of the ulna and the radial head. The proximal and distal radioulnar joints are important in supination and pronation. The proximal and distal aspects of this joint cannot function without each other.⁶⁴

Capsule and Ligaments