composed primarily of auditory ossicle bone http://upload.wikimedia.org/wikipedia/commons/b/b0/Illu_auditory_ossicles.jpg The small bones of the middle ear: incus, malleus, and stapes. [TFD][VHOG] ossicle of ear This should probably be restricted to mammals - the AAO/XAO structures may group non-homologous structures [Wikipedia:Evolution_of_mammalian_auditory_ossicles] see https://github.com/seger/aao/issues/5. ear ossicle ear ossicles XAO:0000214 MA:0000254 EV:0100360 NCIT:C32164 auditory ossicle EHDAA:5697 AAO:0011015 EMAPA:17824 ossicular chain SCTID:181184001 Studies have shown that ear bones in mammal embryos are attached to the dentary, which is part of the jaw. These are ossified portions of cartilage -- called Meckel's cartilage -- that are attached to the jaw. As the embryo develops, the cartilage hardens to form bone. Later in development, the bone structure breaks loose from the jaw and migrates to the inner ear area. The structure is known as the middle ear, and is made up of the incus, stapes, malleus, and tympanic membrane. These correspond to the quadrate, prearticular, articular, and angular structures in the reptile jaw. For this reason, researchers believe the similarity of the results shows that mammals and reptiles have a common ancestry. middle ear bone ossicle UBERON:0001686 ossicle of inner ear middle ear ossicle FMA:52750 ear bone Additional structural analysis within a phylogenetic context has led to the remarkable discovery that in synapsids, thought to be ancestral to mammals, both the quadrate and articular have become reduced and less firmly articulated with their surrounding bones, reducing their jaw-joint-bearing role. This trend culminated with the incorporation of the quadrate, the columella (which remains articulated with the quadrate), and the articular into the expanded middle ear in mammals.[well established][VHOG] EHDAA2:0001183 VHOG:0000461 One of 3 small bones contained within the middle ear space and serve to transmit sounds from the air to the fluid-filled labyrinth. The absence of the auditory ossicles would constitute a moderate-to-severe hearing loss. The term 'ossicles' literally means 'tiny bones' and commonly refers to the auditory ossicles, though the term may refer to any small bone throughout the body. [WP,unvetted]. auditory bone Wikipedia:Auditory_ossicle UMLS:C0013450 bone tissue head bone auditory ossicle endochondral element Christopher J. Mungall