Distal Triceps Tendon

Cranial to the olecranon, US reveals the hypo-echoic bellies of the triceps muscle and its tendon that is located eccentrically and slightly medial with respect to the midline (Fig. 8.21). The distal triceps tendon appears hyperechoic and typically exhibits striations as it fans out toward its insertion on the olecranon, a pattern somewhat similar to the quadriceps. These striations, with alternating hypo- and hyperechoic bands, are more likely due to interposition of fat between the tendon fibers and should not be misinterpreted as tendinosis or tear (Fig. 8.22). If examined in full elbow extension, the distal triceps tendon may also appear wavy, possibly mimicking a rupture. Tendon laxity is particularly evident in the elderly and represents a normal finding (Rosenbe rg... 

Distal triceps tendon tear is an uncommon condition that mostly occurs at or close to the olecranon process of the ulna, often associated with a fleck of bone attached to the retracted tendon as a result of avulsion fracture (Fig. 8.47). The mechanism involves either forced flexion of the elbow against a contracting triceps, as occurs during a fall on an outstretched arm, or relates to a direct blow onto the olecranon process. Local steroid injection into the olecranon bursa, anabolic steroid abuse and pre-existing tendinosis may also have a role in the tendon rupture. As a rule, complete tears occur more... 

Fig. 8.50a-c. Chronic traumatic olecranon bursitis in a manual laborer who had recently injured several times his posterior right elbow, a Midsagittal and b transverse 12-5 MHz US images over the olecranon process (O) show a markedly distended olecranon bursa (arrowheads) containing thick septa (curved arrows) and anechoic effusion (asterisks). Straight arrows, distal triceps tendon, c Photograph showing the bursal lump (arrows) on the posterior elbow... 

Fig. 8.53a,b. Calcific olecranon bursitis in a patient with renal osteodystrophy, a Posterior midsagittal 12-5 MHz US image with b lateral radiographic correlation demonstrates a large calcification (asterisks) that lies superficial to the insertion of the distal triceps tendon (arrowheads) reflecting an extensively calcified bursa. Note the relation of the mass with the posterior olecranon... 

Fig. 8.64a,b. Snapping triceps syndrome. Schematic drawings of the posterior aspect of the elbow in a extension and b 90° flexion demonstrate the ulnar nerve (arrows) as it passes through the cubital tunnel and a prominent medial head (mh) of the triceps muscle (tin). Note the absence of the Osborne retinaculum when compared with Fig. 8.7c. With elbow flexion, the medial edge of the triceps (arrowheads) and the ulnar nerve move anterior to the tip of the epicondyle. T, distal triceps tendon /c , flexor carpi ulnaris...

Fig. 8.71a,b. Synovitis of the elbow joint pitfall. a,b Transverse 12-5 MHz US images over the posterior olecranon recess a in a normal subject and b in a patient with rheumatoid arthritis and an olecranon recess (arrows) appears markedly distended by fluid. In a, the normal hypoechoic fat contained. In b the olecranon fossa, between the lateral (LE) and medial (ME) epicondyles, should not be confused with the synovitis process shown in b. In doubtful cases, careful dynamic examination with elbow flexion and extension movements may be helpful for the diagnosis. Note the erosion (arrowhead) on the posteromedial aspect of the lateral epicondyle. T, distal triceps tendon... 

The posterior compartment includes the triceps and the anconeus muscles. The triceps is a large muscle made up of three heads-medial, lateral and long-from which it derives its name. The muscle bellies converge into a single thick tendon which attaches on the posterior aspect of the olecranon process. To increase the strength of extension of the elbow joint, the triceps tendon does not insert on the tip of the olecranon, but approximately 1 cm distal... 

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