Cavities of Bones are bing discussed.Articular cavities are called Cotyloid, cup-like ; Glenoid, shallow ; Trochlear, pulley-like ; Facet, if smooth ; Alveolar, orAlveoli, when socket-like. Non-articular cavities are named fossae, sinuses,aqueducts, foramina, canals, fissures, notches, cells, grooves, depressions, etc.