BY CATHERINE FISCELLA LOGAN, MSPT
The Elbow Joint
Anatomy, two common injuries and postrehab strategies.
BY CATHERINE FISCELLA LOGAN, MSPT
ends of the bones involved in articulation (Moore 1992).
MUSCLES OF THE ELBOW JOINT
The elbow is a “hinge” joint formed by the distal end of the humerus and the proximal ends of the radius and ulna bones. The elbow moves into flexion and extension. The trochlea and capitulum of the humerus articulate with the trochlear notch of the ulna and the radial head, respectively. The specific articulations of the elbow joint include the humeroulnar and humeroradial articulations and the proximal radioulnar joint. The humeroulnar articulation, which is between the trochlea of the humerus and the trochlear notch of the ulna, permits flexion and extension. The humeroradial articulation is between the capitulum of the humerus and the radial head and allows pronation and supination. The capitulum fits into the slightly cupped surface of the radial head. The proximal radioulnar joint, found between the head of the radius and the ulna’s radial notch, allows rotation of the radius about the ulna (Moore 1992). The two condyles of the humerus (found at the distal end) form the articulating surfaces at the elbow joint. Above the condyles are the lateral and medial epicondyles. The lateral epicondyle is the origin for the forearm extensor muscles, which extend the wrist. The medial epicondyle is the attachment point for the forearm flexor muscles that flex the wrist. A fibrous capsule surrounds and encloses the elbow joint, and medial and lateral thickenings of the capsule create the joint’s intrinsic, or “collateral,” ligaments. The radial collateral ligament is on the lateral aspect of the joint, while the ulnar collateral ligament is on the medial side. The adult elbow joint is quite stable because of the hinge-link articulation between the bones and the strength of the ulnar and radial collateral ligaments. The elbow is not as strong in children because of the late fusion of the epiphyses of the
The principal muscles responsible for elbow extension and flexion are the triceps brachii for extension, and the brachialis, biceps brachii and brachioradialis for flexion. Other muscles involved in extension include the anconeus and brachioradialis. (Although the brachioradialis is primarily a flexor, it also assists in active extension.) Other flexors include the extensor carpi radialis longus, pronator teres and flexor carpi radialis. The pronator teres pronates the forearm, and the anconeus abducts the ulna during pronation. The supinator muscles supinate the forearm, but do not flex or extend the elbow joint (Moore 1992).
ment may include stretching and strengthening as well as therapeutic modalities such as ultrasound, laser, iontophoresis and/or phonophoresis (methods of enhancing drug delivery through electrical current or ultrasound), electrical stimulation, etc.
Individuals who suffer from lateral epicondylitis may have pain or burning in their forearm muscles. The condition is common in tennis players and is therefore given the nickname “tennis elbow.” Lateral epicondylitis may also result from occupations that involve repetitive movements such as raking, painting or using a computer mouse. This injury is typically caused by repetitive microtrauma that results in degeneration of the extensor carpi radialis brevis tendon. Repetitive eccentric muscle overload has been implicated (Brotzman 1996). Less commonly, the extensor carpi radialis longus tendon will be the primary pathology (Kibler, Herring & Press 1998). Chronic overload of the tissue (from a change of activity or from an athletic/ occupational activity), or an acute traumatic fall or direct blow can cause this condition. Symptoms are generally worse during eccentric loading of the extensor muscles. Weakness in the external rotators of the shoulder, resulting in compensatory movement, is sometimes noted (Kibler, Herring & Press 1998). Treatment by a physical therapist or an athletic trainer will depend on what is found during a physical evaluation. TreatOctober 2005 IDEA Fitness Journal
If the injury results from eccentric overload, eccentric strengthening with resistance tubing, as well as strength training with hand weights or dumbbells, is needed to prevent recurrence. Maintenance of elbow flexion and extension and forearm pronation/supination flexibility is also important. Proper form in athletic activities or occupational tasks is essential to avoid reinjury. Strengthening. Strengthening should always be performed in a pain-free range of motion. 1. wrist extension with resistance tubing/band (3 sets, 10