| petrosal fossa | A small and often only faintly marked depression on the inferior surface of the petrous portion of the temporal bone, between the jugular fossa and the opening of the carotid canal; here opens the canaliculus tympanicus transmitting the tympanic nerve. Synonym: fossula petrosa, petrosal fossa, receptaculum ganglii petrosi. (05 Mar 2000) |
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| petrosal impression of the pallium | A shallow impression on the inferior surface of the cerebral hemisphere made by the superior margin of the petrous part of the temporal bone. Synonym: impressio petrosa pallii. (05 Mar 2000) |
| petrosal sinus | See: inferior petrosal sinus, superior petrosal sinus. (05 Mar 2000) |
| petrosal sinus sampling | Sampling of blood levels of the adrenocorticotropic hormone (acth) by withdrawal of blood from the inferior petrosal sinus. The inferior petrosal sinus arises from the cavernous sinus and runs to the internal jugular vein. Sampling of blood at this level is a valuable tool in the differential diagnosis of cushing disease, cushing syndrome, and other adrenocortical diseases. (12 Dec 1998) |
| petrosal vein | <anatomy, vein> A short trunk formed by the union of four or five cerebellar and pontine veins opposite the middle cerebellar peduncle; it terminates in the superior petrosal sinus. See: superior petrosal sinus, inferior petrosal sinus. Synonym: vena petrosa. (05 Mar 2000) |
| hiatus of canal for greater petrosal nerve | The opening on the anterior aspect of the petrous part of the temporal bone which leads to the facial canal and gives passage to the greater petrosal nerve. Synonym: hiatus canalis nervi petrosi majoris, fallopian hiatus, Ferrein's foramen, hiatus canalis facialis, hiatus of canal for greater petrosal nerve. (05 Mar 2000) |
| hiatus of canal of lesser petrosal nerve | <anatomy, nerve> The small opening in the petrous bone lateral to the hiatus of facial canal that gives passage to the lesser petrosal nerve. Synonym: hiatus canalis nervi petrosi minoris, Arnold's canal, canalis nervi petrosi superficialis minoris. (05 Mar 2000) |
| small deep petrosal nerve | <anatomy, nerve> One of two sympathetic branches from the internal carotid plexus to the tympanic plexus. Synonym: nervus caroticotympanicus, small deep petrosal nerve. (05 Mar 2000) |
| superior petrosal sinus | A paired dural venous sinus in the groove along the crest of the petrous temporal bone, connecting the cavernous sinus with the termination of the transverse sinus or beginning of the sigmoid sinus. Synonym: sinus petrosus superior. (05 Mar 2000) |
| superior petrosal sulcus | A groove on the crest of the petrous portion of the temporal bone in which rests the superior petrosal sinus. Synonym: sulcus sinus petrosi superioris, superior petrosal sulcus. (05 Mar 2000) |
| deep petrosal nerve | <anatomy, nerve> The deep petrosal branch of the internal carotid plexus, which joins the greater petrosal nerve at the entrance of the pterygoid canal to provide postsynaptic fibres to nerve of the pterygoid canal. Synonym: nervus petrosus profundus. (05 Mar 2000) |
| inferior petrosal groove | A groove lodging the inferior petrosal sinus, formed by union of similarly named grooves in the petrous part of the temporal bone and the basilar part of the occipital bone. Synonym: sulcus sinus petrosi inferioris, inferior petrosal groove, inferior petrosal sulcus. (05 Mar 2000) |
| inferior petrosal sinus | A paired dural venous sinus running in the groove on the petrooccipital fissure connecting the cavernous sinus with the superior bulb of the internal jugular vein. Synonym: sinus petrosus inferior, Englisch's sinus. (05 Mar 2000) |
| inferior petrosal sulcus | A groove lodging the inferior petrosal sinus, formed by union of similarly named grooves in the petrous part of the temporal bone and the basilar part of the occipital bone. Synonym: sulcus sinus petrosi inferioris, inferior petrosal groove, inferior petrosal sulcus. (05 Mar 2000) |
| lesser petrosal nerve | <anatomy, nerve> The parasympathetic root of the otic ganglion, derived from the tympanic plexus; it leaves the tympanic cavity through the canal for the lesser petrosal nerve and passes within the cranium to the sphenopetrosal fissure, or to the foramen ovale, or to the petrosal foramen through which it descends to reach the otic ganglion; conveys presynaptic parasympathetic fibres from the glossopharyngeal nerve concerned with secretomotor innervation of the perotid gland. Synonym: nervus petrosus minor, lesser petrosal nerve. (05 Mar 2000) |