(dura mater, pachymeninx) n. the thickest and outermost of the three *meninges surrounding the brain and spinal cord. It consists of two closely adherent layers, the outer of which is identical with the periosteum of the skull. The inner dura extends downwards between the cerebral hemispheres to form the falx cerebri and forwards between the cerebrum and cerebellum to form the tentorium. A thin film of fluid (not cerebrospinal fluid) separates the inner dura from the arachnoid.... dura
pl. n. (sing. meninx) the three connective tissue membranes that line the skull and vertebral canal and enclose the brain and spinal cord (see illustration). The outermost layer – the *dura mater (pachymeninx) – is inelastic, tough, and thicker than the middle layer (the *arachnoid mater) and the innermost layer (the *pia mater). The inner two membranes are together called the leptomeninges; between them circulates the *cerebrospinal fluid.... meninges
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