title: Prenatal development of the composite occipito-atlanto-axial synovial joint cavity in the dog.
abstract: In the dog, the synovial cavities of the atlanto-occipital and atlanto-axial joints communicated to form a single large composite joint cavity. The prenatal development of this composite occipito-atlanto-axial joint cavity was studied by examining 26 serially sectioned dog embryos and fetuses that ranged in size from 19 to 68 mm crown-rump length, and were between 30 and 42 days of gestational age. In the composite occipito-atlanto-axial joint, trilaminar interzones developed at 19-22 mm (30-31 days), joint cavities opened at 27-32 mm (33-34 days), and the atlanto-occipital and atlanto-axial cavities first communicated at 48 mm (37 days).
mesh_terms: D000818:Animals; D001268:Atlanto-Axial Joint / Q000196:embryology*; D001269:Atlanto-Occipital Joint / Q000196:embryology*; D004285:Dogs / Q000196:embryology*; D013583:Synovial Membrane / Q000196:embryology*