Figure 25. Pronator syndrome. Photograph (bottom right) shows the area scanned. Sagittal (top left) and transverse (bottom left) US scans show a small anechoic ganglion (arrowheads) compressing the median nerve (arrows) in a 33-year-old woman with numbness of the right palm during compression of the anterior cubital fossa. Compare the right arm (RT) and the normal left arm (LT) (toop right) pronator tunnel regions. Large A = brachial artery. Small A and B are measurements of the size of the median nerve.