Torsion of the tendon of peroneus brevis.

The authors present a previously undescribed torsion located within the tendon of peroneus brevis. The musculotendinous unit of peroneus brevis was isolated from 46 lower extremities of cadavers. A goniometer was constructed and utilized to quantify the degree of torsion located within each peroneus brevis tendon. Torsion was present in all 46 cadaver specimens, with a mean of 38.5 degrees and a range of 26 degrees to 56 degrees. The regional anatomy and biomechanical functions of peroneus brevis are discussed, and proposed bases for the embryologic origins and functional significance of the torsion are presented.