- dura mater
- Pachymeninx (as distinguished from leptomeninx, the combined pia mater and arachnoid); a tough, fibrous membrane forming the outer covering of the central nervous system. SYN: dura [TA], pachymeninx [TA]. [L. hard mother, mistransl. of Ar. umm al-jafiyah, tough protector or covering]- cranial d. [TA] the intracranial d., consisting of two layers: the outer periosteal layer that normally always adheres to the periosteum of the bones of the cranial vault; and the inner meningeal layer that in most places is fused with the outer. The two layers separate to accommodate meningeal vessels and large venous (dural) sinuses. The meningeal layer is also involved in the formation of the various dural folds, such as the falx cerebri and tentorium cerebelli and is comparable to and continuous with the dural mater of the spinal cord. The cranial epidural space is then an artifactual space between the bone and the combined periosteum/periosteal layer of the d. realized only as a result of pathologic or traumatic processes and is neither continuous with or comparable to the vertebral epidural space. SYN: dura mater cranialis [TA], d. encephali, cerebral part of d., d. of brain.- d. encephali cranial d..- spinal d. [TA] single-layered strong membrane, comparable to and continuous with (at foramen magnum) the meningeal layer of the intracranial d. of the brain. It does not (in contrast to the d. of brain) adhere to the enveloping bony structures (vertebrae) or their periosteum, being separated from the latter by a considerable space, the vertebral epidural space—a true space containing the internal vertebral venous plexus embedded in a matrix of epidural fat. SYN: d. spinalis [TA], d. of spinal cord, endorrhachis, theca vertebralis.
* * *du·ra ma·ter 'd(y)u̇r-ə-.māt-ər, -.mät- n the tough fibrous membrane lined with endothelium on the inner surface that envelops the brain and spinal cord external to the arachnoid and pia mater, that in the cranium closely lines the bone, does not dip down between the convolutions, and contains numerous blood vessels and venous sinuses, and that in the spinal cord is separated from the bone by a considerable space and contains no venous sinuses called also dura
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* * *du·ra ma·ter (dooґrə maґtər) [L. â€œhard motherâ€] [TA] the outermost, toughest, and most fibrous of the three membranes (meninges) covering the brain and spinal cord; called also pachymeninx.
Medical dictionary. 2011.