has part has part has_part characteristic of part of has modifier abnormal brain development abnormal primordial meninx morphology abnormal meninx primitiva MP:0009726 MPheno.ontology any structural anomaly of the outermost mesenchymal covering of the developing brain and spinal cord that is composed of tough fibrous connective tissue from which the arachnoid mater, pia mater and dura mater are formed morphology abnormal future meninx