Maternalizing the meninges: A pregnant Arabic legacy

Abstract

(rather flatly called the fetal membrane), the neural tube while Dura/arachnoid/pia maters that invest the central nervous axis busy forming the CNA crowns itself dorsally to form the neural (CNA) are the so-called meninges that to the early Arabic observers crest whose versatility and reach closely compete with those of the seemed nothing less than alumm al-dimagh, meaning the mother CNA and all its offshoots called the nerves. While the CNA may of the brain. Meninx connoting a membrane does poor justice to be assigned the pride of place, the task of housing, protecting, the veritable womb that the maters make, all around the CNA propping, buoying, vascularizing, insulating the whole CNA and and well-beyond in all directions. The maternal status has rightly its ramifications is done by the neural crest cells, with the panache been accorded to uterus for bearing and bestowing a baby, and and perfection of a mother or a set thereof. hence metrium, parametrium, metrorrhagia and so on. Uterine Dura mater-literally, the hard mother-is coextensive with the inflammation is metritis, but meningeal inflammation has never cranio-spinal axis for she houses the latter by splitting to form been materitis, nor has meningeal been substituted by maternal. various coeloms each of which spawns and lodges within it the The Arabic reveric gets aborted the moment the misnomer cranial/spinal bones, a sequence that explains why the same dura meninges take over, a gaffe that usurps the forest for the trees. forms periosteum on the outer side and endosteum on the inner. The evolution of the mater-nal terms makes interesting history. The dura fashions various chambers and partitions to nestle the The Arabic alumm al-dimagh was subdivided by Haji Abbas into CNA, hence meriting the appellation nest mother whose precise alumm al-galidah/jafiyah- the hard mother, and alumm al- projections into the cranium create the props falx cerebri ‘et raqiqah-the tender/soft mother. The Latin equivalents were crassa cerebelli’ and a floor for the occipital lobes, wrongly called the (thick or dense) and tenius (thin or fine). Stephen of Antioch, a tentorium cerebelli. The occipital hammock, made by the nest monk described these in Latin as dura mater and pia mater. Pia mater may be Latinically called the floorum occipiti. The nest should have been tenue, but the monk in Stephen chose the word mater, fashions numerous vascular coelomic spaces to pius (pious) or pia, which has persisted. The concept/term accommodate the low pressure venous sinuses (venae magna) to arachnoid was introduced by Herophilus for the spidery nature of the tissue and was described as a complete cover by the Dutch anatomist Frederick Ruysch. Interestingly, the 3 maters cover the gray and white matters, leading one to muse over their very etymology: Mater, matter, matti, mud, matrix, metrium are all rooted in the universal ma, matru meaning mother. The suffix-ter indicates a state of being, and hence mater, laughter, neuter and so on. For convenience, mater has implied motherhood and matter has connoted materiality. In a manner of speaking, we all carry 5 mothers, within our skulls- 3 maternal and 2 material, all having been derived epigenetically from the neuroectoderm that forms in the dorsal midline of the embryonic plate, that soon dips to form the render them patent under pressure. The nest mater assumes a capacity consistent with the size of its contained CNA, and then fashions the bones to anchor itself afar from its contents. Eucephaly, anencephaly, aneucephaly of various shapes and/or sizes, meningocoels (rightly materoceles) are no bony defects, but a consequence of the decisions taken by the maters and the CNA. Ardrey aphorized that normality is a range, and no fixed, arbitrary average. All the aforelisted ‘normal’ ‘abnormal’ variations are but an integral part of widely encompassing normality. It is of significance that an oligocephalic (1000 ml) brain of Anatole France exercised Voltairean genius, and a brain of 2000 ml may be all dumbwit. Normality and abnormality- as yet undefined- usually reside in the eyes of the beholder.