Number 40. Very important two-way connection between the proximal MMA and everything else. Like a railroad from MMA to the falcotentorial junction… Departing from MMA — first stop is lacrimal branch (13) — the meningolacrimal variant. Next is the orbit — meningophthalmic via the deep recurrent meningeal (41). Next is marginal tentorial — (17, 42, 43) — sometimes all the way straight sinus (26a). So, dont underestimate 40
Meningolacrimal and Meningo-ophthalmic arteries
Classic balance between MMA and orbital territories. Meningolacrimal is more common than meningo-ophthalmic because the latter is less balanced than former. And the reverse is recurrent meningeal. See Opthalmic artery page for more info
Meningolacrimal artery enters the orbit via the “foramen of Hyrtl”.
The small branch (white arrow) connecting the lacrimal artery with the MMA is the sphenoid ridge part
Another example (white arrow is sphenoid ridge branch). Lacrimal blush is peach colored arrows.
Corresponding ICA injection — bulk of orbital supply is from ophthalmic proper
Again, there is a continuum. Bodies don’t read books. In example below, the 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 a rare but important connection to the tentorial arcade (arrow) going backwards — usually supplied by ILT.
Here the proximal MMA runs along the anterior aspect of the middle cranial fossa — not laterally. That is increasingly common with larger MMA takeover of ophthalmic territory (shorter route probably). The sphenoid ridge branch is again white arrow.
Stereo pairs
Next stop is free marginal (marginal tentorial) — the “Bernasconi-Cassinari” — white arrows. The lacrimal branch is arrowheads. There is even supply to the posterior ethmoidal (ball arrow)
2D-DSA of the same case
Stereo
Movie
Another Complete Meningo-ophthalmic below
Note absence of sphenoid ridge branch here — MMA to ophthalmic onnection along the anterior cranial fossa floor
Recurrent meningeal — the reverse. Ophthalmci supply of MMA. More commonly anterior division of MMA only, and less commonly all of it (balance again)
Very old case — frontal branch (red arrows) of MMA supply only. Orange is sphenoid ridge branch.
Another old example below — complete supply of MMA — pink is sphenoid ridge brange
