Assessing the histomorphology, and microscopic composition of the triangular fibrocartilage complex [TFCC] of the wrist joint: A cadaveric observational study

Abstract

TFCC, being a complicated structure, located on the ulnar side of the wrist is composed of multiple distinct anatomic entities which together play a critical role in wrist biomechanics. The anatomy of TFCC has not been extensively studied in the Indian population. To elucidate the microscopic anatomy and composition of the triangular fibrocartilage complex of the wrist joint using haematoxylin-eosin and Verhoff Van Gieson staining methods. Samples collected from 40 specimens (20 right and 20 left limbs) were placed in 10% neutral buffered formalin for fixation. Paraffin-embedded blocks were prepared and tissue sections were taken at 7-micron thickness. The slides were subjected to H&E and VVG staining following standardized protocol. The morphological structure of the seven components of triangular fibrocartilage complexes was assessed. The articular disc consisted of densely packed interlaced fibrocartilage with sparse blood vessels. Radioulnar ligaments showed densely-packed-parallel or interlaced- collagen-bundles. A mixture of tight and loose parallel tissue was observed in the sub-sheath of the extensor carpi ulnaris muscle, the ulnar-triquetral (UTL), and the ulnar-lunate ligament (ULL). Irregular morphological composition and loose connective tissue predominated in the ulnar-carpal meniscus (UCM). Blood vessels were observed in the epi-fascicular/ fascicular areas of the UTL, interstitial region of ULL and UCM. The microscopic anatomy of TFCC was complex owing to the varied nature of its entities. An understanding of the distribution of connective tissue, blood vessels, and elastic fibres would be of immense help in planning arthroscopic procedures.