Coronoid Fossa

The teardrop or hourglass sign is formed by the anterior margin of the olecranon fossa and the posterior margin of the coronoid fossa with the capitellum forming the inferior portion. The capi-tellum and trochlea (if ossified) should be super-... 

Three fat pads lie over the capsule, the anterior over the coronoid fossa, the posterior over the olecranon fossa and a third over the supinator as it wraps over the radius. Fracture, haematoma and effusion into an intact capsule may cause capsular distension, which can distort these fat pads, improving their visibility and identifying occult fractures (Fig. 18.4). In the setting of acute trauma, a visible... 

The articular surfaces of the elbow are contained within the joint capsule, which also encloses non-articular surfaces, including the coronoid, radial fossa and olecranon fossae. It attaches just distal to the coronoid and olecranon processes. The whole of the radial head is within the capsule. 

Origin Temporal fossa and temporal fascia. Insertion Coronoid process and anterior border of the ramus of the mandible. Actions Elevates the mandible (closes the mouth) and retracts the mandible after closure. 

The elbow is one of the most stable joints of the body. In normal states, elbow joint motion ranges approximately from 0° to 150° of flexion and from 75° in pronation to 85° in supination. Elbow extension is limited by contact of the olecranon in the posterior humeral fossa, and tightening of the anterior band of the medial collateral ligament, of the joint capsule and of flexor muscles. On the other hand, the bulk of anterior muscles of the arm, the tension of the triceps and the contact of the coronoid process in the anterior humeral fossa limit elbow flexion. Pronation and supination movements are primarily limited by passive muscle constraints rather than ligaments. 

The joint capsule invests the entire elbow. Anteriorly, it is attached to the humeral shaft just above the coronoid and radial fossae, to the anterior aspect of the coronoid process and to the annular ligament... 

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