Orthopedics

In the post-reduction film, there is a lateral depression in the humeral head (arrow, a Hill-Sachs deformity). A Hill-Sachs deformity is a cortical depression (fracture) in the humeral head that forms as the humeral head hits the glenoid rim during the dislocation.

In the left lateral wrist x-ray, the lunate is dislocated from the rest of the wrist bones but still articulates with the radius. The capitate does not sit within the distal articulation of the lunate and is displaced dorsally. Additionally, a line drawn through the radius and lunate fails to intersect with the capitate. This is consistent with a perilunate dislocation. This is compared to a lunate dislocation, where the lunate itself is displaced and turned ventrally (spilled teacup) and the proximal aspect does not articulate with the radius.

Elbow dislocations are classified by the position of the radio-ulnar joint relative to the humerus.1 Images 1, 2, and 3 show a left posterior elbow dislocation; the radius and ulna (red lines) are displaced posteriorly with respect to the distal humerus (blue line). The lateral view of the elbow most clearly shows this: trochlear notch of the ulna (red line) is empty and displaced posteriorly relative to the trochlea (blue line). There is no associated fracture. Images 4 and 5 show the elbow status-post reduction, demonstrating proper alignment of the distal humerus (blue line) with the radius and ulna (red lines).