Humeral Trochlea

The bone structures about the elbow joint include the proximal ends of the ulna and radius and the distal end of the humerus (Fig. 8.1). The radial head articulates with the humeral capitellum in a pivotal mode and the ulna with the humeral trochlea in a hinge mode. The proximal radio-ulnar articulation is composed of the radial head which revolves within the sigmoid (radial) notch of the ulna allowing pronation-supination movements. These articulations cooperate during complex joint movements allowing a wide degree of flexion, extension and axial... 

Fig. 8.68a,b. Synovitis of the elbow joint posterior joint recess, a Longitudinal 12-5 MHz US image over the posterior olecranon recess with b T2w SE MR imaging correlation in a patient with rheumatoid arthritis presenting with painful elbow and loss of extension. US shows a bulk of hypoechoic synovial pannus fiUing the recess (arrows). Deep to the triceps muscle (tm), the posterior fat pad (asterisks) is elevated by the pannus. Note the prominence of the tip of the olecranon (O) and the humeral trochlea (TR) bulging within the recess... 

Fig. 8.79a,b. Lipoma in a patient with painless soft-tissue swelling over the anterior elhow. a Transverse 10-5 MHz US image over the distal humerus with b Tlw GRE MR imaging correlation demonstrates an oval hypoechoic soft-tissue mass (L) located superficial to the hrachialis muscle (br) that displaces the hrachial artery (a) and the distal hiceps tendon (arrows). In this particular case, the echotexture of lipoma is quite similar to the underlying hrachialis and should not be interpreted as a normal muscle. Asterisk, medial edge of the humeral trochlea... 

The bony structures of the elbow are the distal end of the humerus and the proximal ends of the radius and ulna. The elbow joint complex allows two degrees of freedom in motion flexion/extension and pronation/supination. The elbow joint complex is three separate synovial articulations. The humeral-ulnar joint is the articulation between the trochlea of the distal radius and the trochlear fossa of the proximal ulna. The humero-radial joint is formed by the articulation between the capitulum of the distal humerus and the head of the radius. The proximal radioulnar joint is formed by the head of the radius and the radial notch of the proximal ulna. 

Fig. 18.1a-g. Serial radiographs of the elbow showing the typical sequence of the appearance of the ossification centres, a No ossified centres b capitellum c radial head d internal (medial) humeral apophysis e trochlea f olecranon and g external (lateral) humeral apophysis... 

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