Carotid cave
The carotid cave is a potential dural space formed by the redundant distal dural ring on the medial aspect of the clinoid segment of the internal carotid artery (ICA). It has been reported to be present in ~80% of cadaveric specimens .
Gross anatomy
The clinoid segment of the ICA is bounded by proximal and distal dural rings that are variably adherent to each other on the anterior aspect. The distal dural ring is inclined posteromedially, tightly adherent to the lateral aspect of ICA, but loosely adherent to the medial aspect - creating the potential space that is the carotid cave.
Related pathology
The clinical significance of this region lies in the fact that aneurysms projecting medially from the ICA in this location (commonly referred to as carotid cave aneurysms) may be entirely extradural or may have an intradural component.
If entirely extradural in location, rupture does not produce subarachnoid hemorrhage (SAH). On the other hand, if partially intradural (typically at the neck), then subarachnoid hemorrhage is a possibility, and thus treatment potentially required.
Radiographic features
On imaging (CT, MRI, DSA) the relationship of the aneurysm to the distal dural ring can be difficult to establish. As such, these are called transitional aneurysms, with potential for SAH.