The sphenoparietal sinus of breschet: does it exist? An anatomic study.

BACKGROUND AND PURPOSE: The termination of the superficial middle cerebral vein is classically assimilated to the sphenoid portion of the sphenoparietal sinus. This notion has, however, been challenged in a sometimes confusing literature. The purpose of the present study was to evaluate the actual anatomic relationship existing between the sphenoparietal sinus and the superficial middle cerebral vein. METHODS: The cranial venous system of 15 nonfixed human specimens was evaluated by the corrosion cast technique (12 cases) and by classic anatomic dissection (three cases). Angiographic correlation was provided by use of the digital subtraction technique. RESULTS: The parietal portion of the sphenoparietal sinus was found to correspond to the parietal portion of the anterior branch of the middle meningeal veins. The sphenoid portion of the sphenoparietal sinus was found to be an independent venous sinus coursing under the lesser sphenoid wing, the sinus of the lesser sphenoid wing, which was connected medially to the cavernous sinus and laterally to the anterior middle meningeal veins. The superficial middle cerebral vein drained into a paracavernous sinus, a laterocavernous sinus, or a cavernous sinus but was never connected to the sphenoparietal sinus. All these venous structures were demonstrated angiographically. CONCLUSION: The sphenoparietal sinus corresponds to the artificial combination of two venous structures, the parietal portion of the anterior branch of the middle meningeal veins and a dural channel located under the lesser sphenoid wing, the sinus of the lesser sphenoid wing. The classic notion that the superficial middle cerebral vein drains into or is partially equivalent to the sphenoparietal sinus is erroneous. Our study showed these structures to be independent of each other; we found no instance in which the superficial middle cerebral vein was connected to the anterior branch of the middle meningeal veins or the sinus of the lesser sphenoid wing. The clinical implications of these anatomic findings are discussed in relation to dural arteriovenous fistulas in the region of the lesser sphenoid wing.

Gross and histologic study of the rostral epidural rete mirabile and the cavernous sinus in one-humped camels.

Gross and histologic features of the rostral epidural rete mirabile (carotid rete) and the cavernous sinus in one-humped camels were studied. It was evident that the branches of the carotid rete share a common tunica adventitia with the veins of the cavernous sinus. Transmission electron microscopy of the rostral epidural rete mirabile and the cavernous sinus revealed gap junctions in endothelial cells lining the walls of the arterial rete branches and veins. The internal elastic lamina of rete branches were fenestrated. Some of these structural features could facilitate countercurrent heat exchange between the rete branches and the venous plexus of the cavernous sinus to regulate brain temperature.

Two circulatory routes within the human corpus cavernosum penis: a scanning electron microscopic study of corrosion casts.

The microvascular architecture of the human corpus cavernosum penis was studied by scanning electron microscopy of vascular corrosion casts. The corpus cavernosum was supplied by the penile deep artery. It gave off branches to become either arteries distributed within the corpus cavernosum or those directly supplying the corpus spongiosum urethrae. The former arteries further divided into small arteries which fell into two categories: 1) arteries breaking up into capillaries, and 2) arteries draining directly into the cavernous sinuses. The capillaries were collected into venular networks just beneath the tunica albuginea (the subalbugineal venular plexus), while the cavernous sinuses were collected into venules at the periphery of the corpus cavernosum. These postcavernous venules also received venules from the subalbugineal venular plexus, and left the corpus cavernosum. Thus, two circulatory routes are evident within the corpus cavernosum. These findings suggested that the penile erectile cycle is controlled by hemodynamic changes between these two routes within the corpus cavernosum.

Light and scanning electron microscopical study of the cavernous sinus of the monkey, Macaca fascicularis.

The cavernous sinus of Macaca fascicularis is in many respects similar to the human sinus. It consists predominantly of one main venous channel that, together with the internal carotid artery, occupies a meningo-endocranial compartment lateral to the pituitary gland. Trabeculae are few and do not in any way cause the sinus to appear cavernous. They are mostly flattened in the direction of the main venous channel. Cranial nerves three, four, six and the ophthalmic division of five are all located in the lateral wall of the meningo-endocranial compartment with cranial nerve six located most medially adjacent to the internal carotid artery.

Metastatic infiltration of nerves in the cavernous sinus.

Painful dysesthesia in association with ocular motor palsies characterized intraneural carcinomatous invasion in a 48-year-old man. Transcranial biopsy of the cavernous sinus stopped the pain; the specimen confirmed the diagnosis and provided the rationale for radiation therapy. One year after treatment, the patient was healthy and pain-free, with improved ocular motor function. The source of the carcinoma remains unknown.