Clinoid Tentorial Arcade

Here is the first problem — this important arcade (arrows) has no good name.  Reason being is that it links multiple important stations, and whenever each of these contributes to the arcade, the contributing artery gets a different name.  The arcade runs along the tentorial edge between the anterior and posterior clinoids.  In Lasjaunias, its contributors are named the tentorial branch (via MMA / sphenoid branch — dashed arrow), deep recurrent ophthalmic (ball arrow, via ophthalmic artery), posterior branch (of the ILT — open arrows), and at the tail end the MHT (arrowhead).

The arcade is important, because it links all of the above, with contributions from each of the above being in balance.  Particularly when the ILT or MHT are hypoplastic — in such cases for example the ILT territory may be supplied by the MMA, either via the cavernous branch, or via the sphenoid branch supplying the arcade.  In this way, the MMA can reach all the way to the marginal or lateral tentorial arcades.  Lets see below

“Deep Recurrent Ophthalmic” Supply (ball arrow above). Note that the ILT is hypoplastic — as in pretty much all cases when the arcade is supplied by something else other than ILT

MIP — arcade is marked by arrows, contributing all the way to medial and lateral tentorial arcades (arrowheads)

ILT Supply

ILT is the closest to the arcade, and probably for this reason is the usual principal contributor to it.  Other sources, sometimes from far away, such as the MMA (see below) are seen when the ILT is hypoplastic.  Here it is definitely not, and contributes to the arcade as it should (43)

MMA contribution to the arcade

In example below, the middle meningeal contribution to the orbit includes both classic “meningolacrimal” artery via foramen of Hyrtl (arrowheads), and a superior orbital fissure contribution (dashed arrow) that mainly goes to the posterior ethmoidal foramen (ball arrow).  Neither directly supplies the orbit.  Also present is the connection to the tentorial arcade (arrow) going backwards — again in setting of hypoplastic ILT .

The clival tentorial branch (arrows) heads far posterior to become the marginal tentorial arcade (Bernasconi-Cassinari)

Movie — pause and scroll thru images

Accessory Meningeal Supply of Clival Tentorial Arcade AND Cavernous Sinus

Variations are endless — here is one where recurrent meningeal from ophthalmic supplies frontal MMA territory (below)

Posterior MMA territory is via classic MMA .  However, a very large accessory meningeal (solid arrow) directly supplies the cavernous / ILT region (the ILT is thus hypoplastic) and, via large clival tentorial artery along the free edge, continues as prominent marginal tentorial arcade (dashed arrow) way above the falcotentorial junction — to the inferior sagittal sinus region

Note how separate origin of MMA (grey arrow) and Accessory Meningeal Artery (white arrows) is associated with the superficial course of the IMAX (grey arrowhead).  The marginal tentorial is dashed arrows

Movie — everything is there — stop and scroll thru individual images