Ultrasound ulnar nerve at the elbow

This is an axial view of the left elbow in a patient with subluxation of the ulnar nerve. At the beginning of the video, the medial epicondyle is between the two arrows; the ulnar nerve (right arrow) is in its normal position just lateral to the medial epicondyle. As the elbow is flexed from 70 to 130 degrees, the ulnar nerve pops out of the ulnar groove to a position just medial to the medial epicondyle (left arrow). As the elbow re-extends, the ulnar nerve pops back into the groove. The patient reports a slightly uncomfortable sensation with sudden translocation of the nerve each time the elbow flexion/extension movement is repeated.