Nonmeningeal

Nonmeningeal is an anatomical adjective meaning not related to or not involving the meninges, the protective membranes surrounding the brain and spinal cord. The meninges consist of the dura mater, arachnoid mater, and pia mater. The term is used across disciplines such as anatomy, radiology, and pathology to distinguish structures, lesions, or processes that lie outside the meningeal coverings from those that arise from or invade the meninges.

In imaging and clinical reporting, nonmeningeal describes abnormalities that do not originate from the meninges. For example, nonmeningeal brain tumors arise from brain parenchyma rather than from the meninges, whereas meningiomas are tumors that originate from the meninges. The term can also apply to tissues or spaces outside the meningeal layers, such as bone, scalp, or other nonmeningeal compartments involved in a disease process.

The use of nonmeningeal is relative and context-dependent. It is often paired with other descriptors (for example, intra-axial vs extra-axial, intradural vs extradural) to clarify whether a structure or pathology is associated with the meninges. Because the meninges denote a specific anatomical boundary, nonmeningeal helps emphasize that a lesion or structure lies beyond that boundary or does not originate from it.

In summary, nonmeningeal signifies absence of meningeal involvement and serves as a practical contrast to meningeal in clinical descriptions, imaging reports, and anatomical discussions.