Credit: Alida M. Bailleul, Casey M. Holliday
Micro-computed tomography and histology of the synovial jaw joint of hatchling (a–d), juvenile (e–h) and adult American alligator (i–l) demonstrate articular cartilage-covered joint surfaces and a synovial cavity bounded by a fibrous joint capsule. Three-dimensional CT reconstructions are shown in a hatchling (a), juvenile (e) and an adult alligator (i). Red lines indicate plane of CT and histological sections in (b,f and j), respectively. Associated thin-sections from the white boxes in (b,f and j) are shown, respectively, in (c,g and k) followed by higher magnifications in (d,h,l), respectively. Specimen numbers: OUVC10606 in (a,b), MUVC-AL050 in (c,d), MUVC-AL623 in (e,f), MUVC-AL075 in (g,h), MUVC-AL721 in (i,j), MUVC-AL039 in (k,l). ac, articular cartilage; Ar, articular; cc, calcified cartilage; dct; dense connective tissue; fc, fibrocartilage; ficp, fibrous capsule; fl, fibrous layer; hc, hyaline cartilage; pz, proliferative zone; Qu, quadrate; Qj, quadratojugal; Su, surangular; syc, synovial cavity; sym, synovial membrane.