Anatomical cavities are spaces within the body that contain and protect organs, muscles, and other structures. CECA is an acronym for the four major cavities of the body: Cranial, Thoracic, Abdominal, and Pelvic. ANTRA refers to the two nasal cavities located in the skull, which are separated by the nasal septum. FOSSAE are shallow depressions or grooves in the bones of the skull, which provide attachment points for muscles and ligaments. CREST is a ridge of bone on the skull, which serves as an attachment point for muscles and ligaments. SACS are small, fluid-filled SACS that cushion and protect organs, such as the heart and lungs.