Functional ligamentous anatomy of the trapezium and trapeziometacarpal joint (gross and arthroscopic)

A detailed description of the ligamentous anatomy of the thumb basal joint is presented from a gross, arthroscopic, and functional point of view. All 16 ligaments that stabilize the trapezium and trapeziometacarpal (TM) joint are discussed in association with their presumed functional relevance rega rding trapezial and trapeziometacarpal joint stability. Geometric and mathe matical models are introduced to help describe and support anatomic observa tions with regard to ligament function. The dorsoradial ligament appears to be an important stabilizer of the TM joint against dorsally directed force s. The trapeziotrapezoid, trapezio-II metacarpal, and trapezio-III metacarp al ligaments appear to function as tension bands to help support the trapez ium against cantilever bending forces imparted onto the trapezium by the th umb metacarpal.