Venous Anatomy of the Sphenoparietal Sinus: Evaluation by MR Imaging

Abstract

<jats:p> The termination of the superficial middle cerebral vein (SMCV) has been described as entering or being partially equivalent to the venous sinus coursing under the lesser sphenoid wing, which has classically been called the sphenoparietal sinus. However, the recent literature reports that the SMCV is not connected to the sphenoparietal sinus. In this study, the venous anatomy was evaluated to clarify the anatomy of the sphenoparietal sinus and the termination of the SMCV. Magnetic resonance imaging (MRI) was performed on 1.5-T superconductive units using a three-dimensional fast spoiled gradient-recalled acquisition in the steady state (3-D fast SPGR) sequence with fat suppression in a total of 48 sides of 24 patients. Coronal source images and reconstructed axial images were displayed on the Advantage Window Console, and connections to the cavernous sinus were then evaluated for the venous sinus coursing under the lesser sphenoid wing (hereafter called the sinus of the lesser sphenoid wing), the middle meningeal vein, and the SMCV. </jats:p><jats:p> The following findings were observed bilaterally in all patients. The sinus of the lesser sphenoid wing was connected medially with the cavernous sinus and laterally with the anterior branch of the middle meningeal vein near the pterion. </jats:p><jats:p> The anterior branch of the middle meningeal vein entered the bony canal laterally above the junction with the sinus of the lesser sphenoid wing and coursed along the inner table of the skull or emerged into the diploic vein, indicating its parietal portion. Although the termination of the SMCV had several patterns, the SMCV was not connected with the sinus of the lesser sphenoid wing in any of the patients. The sphenoparietal sinus is considered to consist of the sinus of the lesser sphenoid wing and the parietal portion of the anterior branch of the middle meningeal vein; these were identified as venous structures distinct to the SMCV. </jats:p>

Contrast-enhanced Reformatted MR Images for Preoperative Assessment of the Bridging Veins of the Skull Base

“…San Millán Ruíz et al (38) investigated the venous anatomy of this region in 15 nonfixed cadavers and found no connection between the SMCV and the sphenoparietal sinus in any specimen. Similarly, in the findings from a study by Takahashi et al (39), the SMCV was not connected with the sphenoparietal sinus at contrast-enhanced 3D fast spoiled gradient-echo T1-weighted MR imaging in any of 24 patients. In contrast, other investigators have found a high incidence of connection between the sphenoparietal sinus and the SMCV (32,33,37).…”

“…It connects to the branches of the middle meningeal vein laterally and ends at the anterior aspect of the cavernous sinus medially. The sphenoparietal sinus receives venous drainage from the nearby skull base, namely, from a diploic vein of the orbital roof, a diploic vein of the greater sphenoid wing, and, occasionally, an orbital vein (37)(38)(39).…”

Dural Venous System in the Cavernous Sinus: A Literature Review and Embryological, Functional, and Endovascular Clinical Considerations

“… 12 , 14 , 15) Our general understanding of the sphenoparietal sinus is that it is a large meningeal channel that runs medially just below the lesser sphenoid wing to empty into the anterior part of the CS, usually the SMCV flows into this sinus. 2) However, Ruíz et al 15) and Takahashi et al 18) recently questioned this classical understanding of the sphenoparietal sinus. They described two independent venous channels (the sinus of the lesser sphenoid wing and the SMCV) that exist in this region, and they found no connections between these two venous channels.…”

“…15) It drains diploic veins from the orbital roof and the greater sphenoid wing without venous connection to the SMCV. 15 , 17 , 18) The CS has connections medially to the opposite side of the CS through intercavernous sinuses. Green 46) described that anterior and posterior intercavernous sinuses receive some osseous veins from the lateral part of the posterior clinoid plate.…”

Idiopathic middle meningeal artery and middle meningeal vein fistula presenting as temporal intraparenchymal hemorrhage

“…The MMV is depicted to run within the grooves of the skull with the accompanying MMA, and is partly drained into the sphenoparietal sinus and the emissary veins through the foramen spinosum. 10 One previous study histologically confirmed and precisely described the MMA and MMV running side by side nearby the foramen spinosum and pterion, and running separately at the parietal bone. 11 Our case highlights the anatomy of the course of the MMV, and the proximity of the MMA and MMV near the foramen spinosum.…”