Article Figures & Data
Figures
- FIG 1.
Schematic drawing of the potential venous pathway between the SPS and the EVFO. Two known routes include the medial route through the cavernous sinus (CS) and the lateral route through the petrosquamosal sinus (PSqS) and the middle meningeal sinus (MMS). There is another unknown route running on the superior surface of the petrosal bone connecting directly between the EVFO and the SPS (red dotted line). PV indicates petrosal vein; IPS, inferior petrosal; TS, tentorial sinus.
- FIG 2.
Lateral view on left vertebral angiography in the venous phase showing a venous channel (arrows) arising from the midportion of the SPS that runs anterior-inferiorly to join the EVFO. It is provisionally named the PBV.
- FIG 3.
A case of a dAVF involving the SPS with a drainage route via the PBV. A, Lateral view on right internal carotid angiography shows a dAVF fed by multiple feeders from the meningohypophyseal trunk. The dAVF drains retrogradely via the various petrosal veins into the cerebellar cortical veins and the lateral mesencephalic vein. There is another drainage route via the PBV (arrows) into the emissary vein of the foramen rotundum. B, Axial MPR images based on rotational angiography of the right ICA show the dAVF involving the SPS. A drainage route (white arrow) via the PBV arising from the anterior aspect of the SPS to the EVFO is noted. C, Selective venography via a microcatheter shows transvenous introduction of the microcatheter into the petrosal vein via the PBV. Thereafter, the dAVF was completely occluded by transvenous embolization.
- FIG 4.
PBV visualized on vertebral angiography alone. A, Lateral view on left vertebral angiography in the venous phase shows the PBV (arrows) from the superior petrosal sinus at the confluence of the petrosal vein. The PBV runs anterior-inferiorly to join the emissary vein of the foramen ovale. Axial (B) and sagittal (C) MPR images based on rotational angiography of the right VA show the PBV (arrows) from the anterior aspect of the SPS. It runs anteriorly on the superior surface of the petrosal bone to join the EVFO.
- FIG 5.
Internal carotid angiography showing the PBV as part of the drainage route of the superficial middle cerebral vein (combined type of the sphenobasal and the sphenopetrosal veins). Frontal (A) and lateral (B) views on left internal carotid angiography in the venous phase show the combined sphenobasal and sphenopetrosal drainage type of the SMCV. The PBV (arrows) composes part of the termination of the SMCV between the EVFO and the SPS. Axial (C, next page) and sagittal (D, next page) MPR images based on rotational angiography of the left ICA show the PBV (arrows) running anterior-posteriorly between the midportion of the SPS and the EVFO. The SMCV joins the EVFO.
- FIG 6.
Schematic drawing of the embryologic development of the SPS, EVFO, and SMCV. A, Lateral view of an embryo at 18–26 mm in crown rump length. ADpxS indicates anterior dural plexus stem; PHS, primary head sinus; OV, otic vesicle; pSOV, primitive superior ophthalmic vein; pMax, primitive maxillary vein; DPV, dorsal pharyngeal vein; MDpxS, middle dural plexus; STV, superficial telencephalic vein; Met, metencephalic vein; IPS, inferior petrosal sinus; V, trigeminal nerve; VDV, ventral diencephalic vein. The dotted lines indicate regressed parts of the ADpxS and PHS. The dorsal part of the MDpxS forms the posterior part of the SPS in the future. The peritumoral venous ring surrounds the trigeminal nerve, and it connects the distal and proximal portions of the prootic sinus (proOS). B, View a few weeks after that shown in A. DTV indicates deep telencephalic vein; V3, mandibular nerve; Met, metencephalic vein; PSqS, petrosquamosal sinus; FO, foramen ovale; CS, cavernous sinus; SOV, superior ophthalmic vein. The anterior part of the MDpxS and inferior ramus of the paratrigeminal venous ring disappear, and the remnant of the superior ramus of the venous ring and the residual posterior portion of the MDpxS form the primary SPS. The DPV runs along the V3, which connects with the pterygoid venous plexus through the FO to become the EVFO. C, View just before or after birth. The PTS deviates inferomedially (red arrows) to the middle cranial fossa close to the FO secondary to further development of the temporal lobe. D, Common venous system type in adults. The PTS is further deviated medially (red arrows) and fuses to the CS, and the SMCV and uncal vein (UV) drain into the CS. The midportion of the PTS fuses to the primary SPS. A remnant of the posterior part of the PTS becomes the lateral and/or medial tentorial sinus. The metencephalic vein becomes the petrosal vein. E, The PBV combined with the sphenobasal vein. In this type, the anterior and midportions of the PTS remain at the middle cranial fossa and fuse to the EVFO. Venous blood from the SMCV drains into the EVFO and the SPS via the PBV. Venous blood from the SPS can also be drained via the PBV into the EVFO, depending on the pressure gradient. F, The PBV alone. In this type, the midportion of the PTS remains alone at the middle cranial fossa. The anterior part fuses to the CS. Venous blood from the SMCV drains into the CS. Venous blood from the SPS partially drains via the PBV into the EVFO.
