Topography and Course
The artery originates from the first (mandibular) part of the maxillary artery (a. maxillaris), running between the neck of the mandibular condyle and the sphenomandibular ligament.
It ascends to enter the cranial cavity through the foramen spinosum. Within the cranium, the artery courses across the squamous part of the temporal bone and the greater wing of the sphenoid bone, running along the external surface of the dura mater. It is the largest of the dural arteries and supplies the entire lateral (convex) surface of the cranial vault.
Branches of the Middle Meningeal Artery
Within the cranial cavity, the vessel divides into a frontal branch (r. frontalis) and a parietal branch (r. parietalis), which course along the outer surface of the dura mater.
Additional branches arising from the main trunk include:
- Superior tympanic artery (a. tympanica superior) — travels to the mucous membrane of the tympanic cavity.
- Petrosal branch (r. petrosus) — runs toward the canal for the greater petrosal nerve.
- Orbital branch (r. orbitalis) — courses toward the orbit.
- Pterygomeningeal artery (a. pterygomeningea) — supplies the pterygoid muscles, auditory tube, and dura mater.
- Anastomotic branch with the lacrimal artery (r. anastomoticus cum a. lacrimali).
Anastomoses and Clinical Significance
The middle meningeal artery anastomoses within the orbit with the lacrimal artery (a. lacrimalis), which is a branch of the ophthalmic artery (originating from the internal carotid artery).
Clinical significance: In occlusion of the ophthalmic artery proximal to the origin of the central retinal artery, collateral blood flow from the middle meningeal artery via this anastomosis can preserve retinal perfusion. The anterior and posterior meningeal arteries also anastomose with the middle meningeal artery.
Cranial Projection (Krukenberg-Krenlein Scheme)
Craniocerebral topography (Krenlein's lines) is used to localize the vessel:
- Main trunk: Projects onto the intersection of the anterior vertical line (drawn through the midpoint of the zygomatic arch) and the lower horizontal line (drawn through the infraorbital margin and the upper border of the external acoustic meatus). This point lies near the upper border of the zygomatic arch, 2.0–2.5 cm posterior to the frontal process of the zygomatic bone.
- Frontal branch: Projects onto the intersection of the anterior vertical line and the upper horizontal line.
- Parietal branch: Projects onto the intersection of the posterior vertical line and the upper horizontal line.
Clinical Significance and Trauma
- Epidural hematomas: In traumatic brain injuries, the middle meningeal artery or its branches are the source of hemorrhage in about 80% of cases.
- Anesthesia risks: The vessel can be injured during regional anesthesia of the mandibular nerve (V3) near the foramen ovale.
- Surgery: During decompressive craniectomy, expanding a burr hole in an anteroinferior direction carries the risk of lacerating the arterial trunk. If injured, the peripheral stump is typically ligated with a transfixing suture, while the central stump within the bony canal is sealed with bone wax.