Proximal dural ring
Annulus durale proximale
- Synonym: Carotid-oculomotor membrane
Definition
The proximal dural ring (or carotid-oculomotor membrane, COM) is a part of the connective fold that extends from the inner layer of the lateral wall of the cavernous sinus to the inferior aspect of the anterior clinoid process and optic strut, and to the anterior loop of the internal carotid artery.
The proximal dural ring marks the transition of the cavernous (C4) to the clinoid (C5) segment of the internal carotid artery (ICA).
The proximal dural ring lines the lower margin of the anterior clinoid process and separates the anterior clinoid process from the oculomotor nerve, extending from the oculomotor nerve medially to surround the internal carotid artery, forming a distinct ring only on the anterior and lateral margins of the artery. The ring is incomplete on the medial side of the internal carotid artery.
References
Beretta F, Sepahi AN, Zuccarello M, Tomsick TA, Keller JT. Radiographic imaging of the distal dural ring for determining the intradural or extradural location of aneurysms. Skull Base. 2005;15(4):253-262. doi:10.1055/s-2005-918886
