Medial wall of the cavernous sinus

The medial wall (MW) of the cavernous sinus (CS) was studied to define its structure, position and relations with the other CS structures. The study was performed on twenty-five fresh cadaver specimens featuring the sellar and both parasellar regions and parts of the anterior, middle and posterior cranial fossa. Fifteen specimens were injected with auto-polymerizing two component colored substance while ten were left non injected. The uppermost membranous part of the MW of the CS was found dividing the pituitary gland from the CS on each side. This membrane represented the most lateral part of the dural capsule surrounding the pituitary gland and invariably showed its completeness. The position and shape of the MW of the CS was found to be determined by ligaments anchoring it to the nearby bone and dural formations: anteriorly it was anchored to the middle clinoid process (MCP), posteriorly to the dorsum sellae and posterior clinoid process (PCP), superiorly to the diaphragm sellae and the posterior interclinoid ligament and inferiorly to the lateral surface of the sphenoid body. The position of the MW of the CS and the shape of its points of anchorage were found to be the most important factors determining the presence, configuration and size of the entry points of the intercavernous venous communications through the sella. The knowledge of the MW of the CS could have implications both on neuroradiological interpretation and on surgical planning and treatment of lesions involving these regions.