part of part of temporal bone petrous part of temporal bone http://upload.wikimedia.org/wikipedia/commons/9/96/Gray137.png petrosal UMLS:C1261761 VHOG:0001553 NCIT:C32316 MESH:D010579 Wikipedia:Petrous_part_of_the_temporal_bone The petrosal bone arises from the two otic bones on the lateral wall of the chondrocranium and encases the inner ear of mammals. [Bemis_WE, Functional_Anatomy_of_the_Vertebrates:_An_Evolutionary_Perspective, Grande_L, Third_Edition_(2001)_Orlando_Fla.:_Harcourt_College_Publishers, Walker_WF, p.258, see_Liem_KF][VHOG] SCTID:361733004 petrosal bone EMAPA:17683 UBERON:0001694 temporal bone petrous part pars petrosa (os temporale) FMA:52871 EHDAA2:0001452 derivative of prootic and opisthotic petromastoid part of temporal bone petrous bone MA:0001477 The petrous portion of the temporal bone or pyramid is pyramidal and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents for examination a base, an apex, three surfaces, and three angles, and contains, in its interior, the essential parts of the organ of hearing. The petrous portion is among the most basal elements of the skull and forms part of the endocranium.[WP,unvetted]. pars petrosa ossis temporalis GAID:234 basicranium zone of bone organ