This vascular injection study of the triangular fibrocartilage (TFC) was carried out in 12 fresh cadaver arms--eight adults and four infants--with Ward's blue latex. The TFC receives its blood supply from (1) the ulnar artery through its palmar and dorsal radiocarpal branches, (2) the dorsal branch of the anterior interosseous artery, and (3) the palmar branch of the anterior interosseous artery. These vessels are arranged in a radial fashion in relation to the fibrocartilage. Histologic sections of the TFC reveal vascularity in the outer 15% to 20% of the disc, and the rest is avascular. On the basis of these findings, we feel that tears of the TFC in its vascular zone have the potential to heal if repaired and those in the central avascular zone do not have this potential.