MRI of the Wrist

Marcos Loreto Sampaio, MD; Nicholas M. Kolanko, MD


Appl Radiol. 2014;43(10) 

In This Article

Triangular Fibrocartilage Complex (TFCC)

The TFCC is composed of the triangular fibrocartilage proper (TFC) and its periphery. The TFC demonstrates low signal intensity on all sequences and a smooth, biconcave morphology, attaching to the hyaline cartilage of the radius at one margin, and to the ulnar styloid and fovea at the other margin as two low-signal bands (Figure 8). Between these bands is a moderate-to-high-signal-intensity vascularized fibrous tissue(ligamentum subcruentum).[19] The remaining structures of the periphery, including the homologue meniscus, the ulnar collateral ligament, and the sheath of the extensor carpi ulnaris tendon, among others, are more difficult to confidently depict and isolate.

Figure 8.

Normal TFCC. Coronal PD-weighted image with fat suppression. Triangular fibrocartilage proper (*). Foveal (arrow) and styloid (dashed arrow) insertions. Meniscus homologue (arrow head). Normal lunotriquetral (LTL) and scapholunate (SLL) ligaments are also seen.

Owing in part to these characteristics, injuries of the TFC proper are confidently depicted by MRI; they include degenerative signal changes, non-communicating defects (or partial tears) of the surfaces, and communicating defects (full-thickness tears). Degeneration and central/membranous tears can be seen in asymptomatic individuals, and their prevalence increases with patient age (Figure 9). Peripheral injuries are less accurately diagnosed. A peripheral tear is suspected if high signal intensity along the ulnar insertions, detachment from the ulna, or synovitis are present. Intravenous contrast or MR arthrography with injection in the distal radio-ulnar joint may be necessary in such cases.[21] Note that peripheral non-communicating defects have been more commonly associated with symptoms, typically as localized ulnar-sided wrist pain.[22] (Figure 10).

Figure 9.

TFC tear. Coronal PD-weighted image with fat suppression reveals full-thickness tear of the TFC (arrow) close to the radial attachment. There is fluid in the distal radioulnar joint.

Figure 10.

Peripheral tear of the TFCC. Coronal PD-weighted image with fat suppression. Indistinction and high signal intensity of the ulnar insertions of the TFC (arrow), with fluid traversing the area.