part of temporal bone petrous part of temporal bone petrosal EMAPA:17683 temporal bone petrous part pars petrosa (os temporale) FMA:52871 VHOG:0001553 EHDAA2:0001452 NCIT:C32316 MESH:D010579 petromastoid part of temporal bone Wikipedia:Petrous_part_of_the_temporal_bone petrous bone SCTID:361733004 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 petrosal bone GAID:234 basicranium zone of bone organ