Figure 22. Ulnar nerve dislocation. Photographs (bottom) show the area scanned in extension and flexion. Transverse US scans of the elbow in extension and flexion in a 25-year-old man complaining of occasional numbness of the fourth and fifth fingers show an unusual location of the ulnar nerve (arrowheads), lateral to the medial epicondyle in extension but medial to the medial epicondyle during flexion E = medial epicondyle.