![]() ![]() The physis is relatively thick in infancy and childhood and is therefore more prone to injury secondary to shear or tensile forces. The mechanism for physial injuries also varies depending on the age of the patient. Radiographic evaluation of the pediatric elbow is often challenging because of the cartilaginous nature in early infancy followed by the variable appearance of the ossification centers about the elbow joint. The lateral compartment consists of the common extensor tendons, which originate from the lateral epicondyle, the supinator, and the brachioradialis muscles. The medial compartment includes the common flex- or tendons of the wrist and hand, which originate from the medial epicondyle, and the pronator teres. Avulsion injury of the triceps tendon at its attachment to the olecranon is rare in both children and adults. The triceps and anconeus muscles compose the posterior compartment. Uncommonly, the biceps tendon may avulse off the radial tuberosity. Brachialis injuries may be seen in older teenage athletes who rock climb. The anterior compartment consists of the brachialis and biceps muscles. MRI also reveals the muscular compartments about the elbow. The posterior and transverse bundles are not well depicted on MRI but form the floor of the cubital tunnel along with the joint capsule. The transverse bundle of the ulnar collateral ligament stretches between the olecranon and coronoid processes and is formed from horizontally oriented joint capsule fibers. The posterior bundle of this ligament is a fan-shaped thickening of the capsule that is best visualized when the elbow is flexed. The anterior bundle of the ulnar collateral ligament is primarily responsible for valgus stability for the elbow. Along the medial elbow is the ulnar collateral ligament complex ( Fig. The radial collateral ligament proper originates from the lateral epicondyle and inserts onto the annular ligament and fascia of the supinator muscle. The annular ligament surrounds the radial head circumferentially and is the primary stabilizer of the proximal radioulnar joint. This ligament is situated posteriorly within the radial collateral ligament complex, arising from the lateral epicondyle and coursing obliquely across the radius to insert on the ulna at the crista supinatoris. The most important component is the lateral ulnar collateral ligament. The lateral, or radial collateral, ligament complex provides varus stability to the elbow ( Fig. The medial and lateral portions of the joint capsule are thickened to form the collateral ligament complexes, depicted by MRI ( Fig. ![]() The triceps muscle inserts onto the olecranon. The anteroinferior surface of the coronoid process along with the ulnar tuberosity serve as the insertion sites for the brachialis muscle. The ulnar coronoid process and olecranon articulate with these humeral fossae, respectively. The opposing coronoid and olecranon fossae form the hourglass configuration of the distal humerus identified on the lateral radiograph (Figs. The olecranon fossa is on the dorsal surface of the distal humerus. Īlong the ventral surface of the distal humeral metaphysis are two depressions: the coronoid fossa medially and the radial fossa laterally. The proximal radial metaphysis is referred to as the radial neck, whereas the radial tuberosity serves as the insertion for the biceps tendon. Along the lateral elbow, the capitellum articulates with the radial head. ![]() The concavity along the anterior aspect of the proximal ulna is called the trochlear notch, or semilunar notch, which articulates with the humeral trochlea. The medial and lateral epicondyles are situated superior to the articular surfaces. The trochlea and capitellum comprise the articular surfaces of the medial and lateral columns, respectively. ![]() The medial column deviates from the long axis of the humerus at approximately twice the angle of the lateral column, accounting for the bony eminence palpated along the medial elbow. The distal humerus flares outward in the coronal plane to form medial and lateral columns. Rather, it functions primarily as a hinge joint. The elbow has little intrinsic osseous stability. The elbow is a complex joint consisting of three osseous articulations and multiple ligamentous and myotendinous attachments, both proximally and distally (Figs. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |