| cerebral part of arachnoid | That portion of the arachnoid which lies within the cranial cavity and surrounds the brain and the cranial portion of the subarachnoid space. In several sites it is relatively widely-separated from the pia mater, creating the cranial subarachnoid cisterns. Synonym: arachnoid mater cranialis, arachnoid mater encephali, cerebral part of arachnoid. (05 Mar 2000) |
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| pia-arachnoid | The two delicate layers of the meninges, the arachnoid mater and pia mater (vs. The tough pachymeninx or dura mater), considered together; by this concept, the arachnoid and pia are two parts of a single layer, much like the parietal and visceral layers of a serous membrane or bursa; although separated by the subarachnoid space they are connected via the arachnoid trabeculae and become continuous where the nerves and filum terminale exit the subarachnoid space (the cerebrospinal fluid-filled space bounded by the leptomeninges). See: arachnoid, pia mater. Synonym: meninx tenuis, pia-arachnoid, piarachnoid. Origin: Lepto-+ G. Meninx, pl. Meninges, membrane (05 Mar 2000) |
| spinal part of arachnoid | That portion of the arachnoid which lies within the vertebral canal and surrounds the spinal cord and the vertebral portion of the subarachnoid space. It extends from the foramen magnum above to the S-2 vertebral level. Since the spinal cord ends at the L-2 vertebral level, a wide separation occurs between the arachnoid and pia mater, the lumbar cistern, filled with cerebrospinal fluid in which the cauda equina is suspended. Synonym: arachnoidea mater spinalis, spinal part of arachnoid. (05 Mar 2000) |
| alma mater | A college or seminary where one is educated. Origin: L, fostering mother. Source: Websters Dictionary (01 Mar 1998) |
| arachnoidea mater spinalis | That portion of the arachnoid which lies within the vertebral canal and surrounds the spinal cord and the vertebral portion of the subarachnoid space. It extends from the foramen magnum above to the S-2 vertebral level. Since the spinal cord ends at the L-2 vertebral level, a wide separation occurs between the arachnoid and pia mater, the lumbar cistern, filled with cerebrospinal fluid in which the cauda equina is suspended. Synonym: arachnoidea mater spinalis, spinal part of arachnoid. (05 Mar 2000) |
| mater | The "sheltering" coverings of the central nervous system. Origin: L. Mother (05 Mar 2000) |
| cerebral part of dura mater | The intracranial dura mater, consisting of two layers: the outer periosteal layer which normally always adheres to the periosteum of the bones of the cranial vault; and the inner meningeal layer which 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 a potential space between the bone and the combined periosteum/periosteal layer of the dura mater realised only pathologically and is neither continuous with or comparable to the vertebral epidural space. Synonym: dura mater cranialis, dura mater encephali, cerebral part of dura mater, cranial epidural space. (05 Mar 2000) |
| meningeal layer of dura mater | See: dura mater of brain. (05 Mar 2000) |
| periosteal layer of dura mater | See: dura mater of brain. (05 Mar 2000) |
| pia mater | <anatomy> The delicate and highly vascular membrane immediately investing the brain and spinal cord. Origin: NL, fr. L. Pia (fem. Of pius tender, kind) + mater mother. Source: Websters Dictionary (01 Mar 1998) |
| sinuses of dura mater | Endothelium-lined venous channels in the dura mater. Synonym: sinus durae matris, cerebral sinuses, cranial sinuses, sinuses of dura mater, venous sinuses. (05 Mar 2000) |
| dura mater | <anatomy> The outermost, toughest and most fibrous of the three membranes (meninges) covering the brain and spinal cord. Synonym: pachymeninx. Origin: L. = hard mother (18 Nov 1997) |
| dura mater encephali | An alternate term for dura mater of brain. (05 Mar 2000) |
| dura mater of brain | The intracranial dura mater, consisting of two layers: the outer periosteal layer which normally always adheres to the periosteum of the bones of the cranial vault; and the inner meningeal layer which 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 a potential space between the bone and the combined periosteum/periosteal layer of the dura mater realised only pathologically and is neither continuous with or comparable to the vertebral epidural space. Synonym: dura mater cranialis, dura mater encephali, cerebral part of dura mater, cranial epidural space. (05 Mar 2000) |
| dura mater of spinal cord | Single-layered strong membrane, comparable to and continuous with (at foramen magnum) the meningeal layer of the intracranial dura mater of the brain. It does not (in contrast to the dura mater 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. Synonym: dura mater spinalis, endorrhachis, theca vertebralis. (05 Mar 2000) |