Anatomy, histology, and ontogeny of the sesamoid cartilage in the jaw muscles of the American alligator (Alligator mississippiensis) [abstract]

Abstract

The cartilago transiliens is a characteristic cartilaginous nodule inside crocodilian jaw muscles. Encased by a fibrous sheath, the cartilago transiliens lies between the pterygoid buttress and the mandible, providing attachment sites for m. pseudotemporalis superficialis dorsally, and m. intramandibularis, ventrally. Previous research showed that the cartilago transiliens functions as a jaw-locking mechanism and bears sesamoid-like features, rather than those of a novel structure. Fibrocartilages often form inside portions of tendons that wrap around bone. These organized, incompressible sesamoid tissues prevent tendon flattening, increase mechanical advantage, and tend to ossify in mammals and reptile limbs, but not in most other instances. Here we investigate the gross anatomy and microstructure of the cartilago transiliens in the American alligator (Alligator mississippiensis).