Dura Mater

The dura mater (Latin: dura mater, Greek. pachymeninx) — it is the outermost, thickest, and strongest of the three connective tissue membranes that protect the brain and spinal cord.

It forms a dense, non-elastic fibrous sac that lines the cranial cavity from the inside, serving as a reliable barrier between the bones and the delicate neural tissue.

Etiology and pathophysiology

At the level of the brain, this membrane has a unique two-layered structure. The external layer is very closely fused with the inner surfaces of the cranial bones, effectively serving as their inner periosteum. The internal layer is oriented toward the brain. In certain areas, these two layers diverge, forming rigid triangular channels called venous sinuses, through which oxygen-depleted blood drains from the brain to the jugular veins of the neck.

Moreover, the internal layer forms robust partitions (projections), which deeply invaginate into the fissures between brain sections. The largest of these are the cerebral falx, which separates the right and left hemispheres, and the tentorium cerebelli, which separates the occipital lobes from the posterior cranial fossa. These partitions fix the brain rigidly in place, preventing its critical displacement during sudden head movements.

Clinical significance

The dura mater is richly innervated by branches of the trigeminal nerve. The brain itself does not have pain receptors, so almost any severe headache (including those related to trauma or meningitis) is actually associated with mechanical stretch or chemical irritation of the dura mater.

In traumatology, two spaces associated with this structure hold critical significance. The space between the bone and the dura mater (epidural) is normally absent, but if an artery ruptures, blood is pumped with high pressure into this space, detaching the membrane from the bone. The space beneath the dura mater (subdural) is where venous blood accumulates during the rupture of bridging veins in the pathogenesis of subdural hematomas. Both conditions require urgent neurosurgical intervention.