petrosal

Petrosal is an anatomical term used to describe things related to the petrous part of the temporal bone of the skull, or, in some texts, to the petrosal (petrous) bone in certain vertebrates. The petrous part, sometimes called the petrous pyramid, is a dense, rock-like portion of the temporal bone that forms a large portion of the base of the skull and lies at the skull’s internal ear region.

Anatomy and landmarks: The petrous part encloses the sensory apparatus of the inner ear, including the cochlea and vestibular apparatus, together with portions of the middle ear and their relations. It contains important openings such as the internal auditory meatus, through which cranial nerves VII (facial) and VIII (vestibulocochlear) pass. The carotid canal, through which the internal carotid artery travels, runs within the petrous bone. The petrous apex is a notable upper region, and the petrous portion forms part of the boundary of the tympanic cavity and middle ear. The jugular foramen sits in proximity to the inferior surface of the petrous temporal bone.

Clinical and comparative notes: In clinical practice, fractures or disease of the petrous temporal bone (petrous or petrosal region) can cause hearing loss, vertigo, facial nerve palsy, or cerebrospinal fluid leaks. The term appears in paleontological and anatomical discussions as well, where “petrosal bone” can denote the bony element housing inner ear structures in various vertebrates, informing evolutionary and phylogenetic analyses. In otologic surgery and radiology, detailed knowledge of petrosal anatomy is essential for safe access to the inner ear and related neurovascular structures.

Etymology: Petrosal derives from Latin petrosus (stony, rock-like), itself from petra (rock). It reflects the dense, stone-like nature of this region of the temporal bone.