Anatomical variables of the triangular fibrocartilage complex of the wrist

Abstract

The lesion of the triangular fibrocartilage complex (TFCC) is one of the main causes of wrist pain. The TFCC is an anatomical structure located on the ulnar edge of the wrist, between the ulna and the proximal carpal row. It consists of: the articular fibrocartilage, the homologous meniscus, radio-ulnar ligaments (palmar and dorsal), ulnar-carpal ligaments, the tendon sheath of the carpi ulnar extensor and the ulnar-carpal joint capsule. It serves as a stabilizer of the distal radio-ulnar joint, ulnar-carpal and participates in the prono-supination movement.

The objective of this investigation was to describe possible anatomical variants of the wrist TFCC in cadavers.

A descriptive and analytical study was performed in the Chair of Normal Anatomy (FCM - UNC) in which 9 cadaveric pieces (fixed in 10% formalin) were dissected. With classical dissection by dorsal region, with a 3cm transverse cutaneous incision that runs over the ulnar side, at the level of the sixth extensor compartment and on the radial side to the dorso-ulnar region of the radius epiphysis, a flap of the extensor retinaculum is raised to ulnar base, sectioning some weak insertions that it has with the dorsal capsule of the distal radio-ulnar joint and the fibrous arch of the posterior ulnar. The extensor tendons of the fifth finger and the posterior ulnar are exposed, these tendons are separated to access the dorsal capsule to proximal and to triangular to distal fibrocartilage. A "T" capsulotomy is performed to access the structures under study. The elements of the TFCC were identified, describing their specific insertions and relationships, recording probable variations of their anatomy.

In 2 specimens we found variations in the homologous meniscus relationship. One specimen presented an insertion to the lunate-pyramidal ligament distally and in another specimen an insertion to the ulnar collateral ligament. The rest of the structures evaluated were presented with their insertions and relationships described traditionally.

Despite the limited number of dissected pieces, we were able to show variability in the configuration of the TFCC, which motivates to deepen the anatomical study of this structure.