Triangular fibrocartilage complex (TFCC)

ANATOMY The TFCC is a fibrocartilage-ligament complex which stabilizes the distal radioulnar joint (DRUJ), transmits axial load between the carpus and the ulna, and stabilizes the ulnar aspect of the carpus. The TFCC is comprised of the disc proper (articular disc), meniscus homologue, ulnolunate ligament, ulnotriquetral ligament, proximal ligamentous component, volar and dorsal radioulnar ligaments, and the ulnar collateral ligament. Because these structures are located in small areas, high-resolution imaging is essential to diagnose TFCC injuries. In coronal MR images, disc proper, triangular ligament, meniscus homologue, ulnotriquetral ligament are appreciated, and in axial plane images, volar and dorsal radioulnar ligaments are well recognized. The normal disc proper shows asymmetrical bowtie-like low signal intensity. The signal intensity of the ulnar attachment of the TFCC was higher than that of the disc proper on proton density-weighted images and T2*-weighted images. Most of the TFCC have two attachments to the ulna, inserting into the ulnar styloid tip (distal lamina) and the fovea (proximal lamina). The tissue between two triangular ligaments is called ligamentum subcruentum. Three main arterial branches supply the TFCC: 1) the ulnar artery, 2) the palmar branch of the anterior interosseous artery, and 3) the dorsal branch of the anterior interosseous artery. The dorsal branch of the anterior interosseous artery runs on the dorsal side, while the palmar