area (a're-ah)

A surface, district or space, without reference to its size or shape, a. intercrural is. The inter peduncular space of the brain, a. lucid a. See transparent a. a. mammae. The areola surrounding the breast, a. Martegiani. The funnel-shaped opening of the hyaloid canal on the posterior surface of the vitreous body. a. obscura, a. opaca. See opaque a. a. optic a. The visual field. a. pellucid a. See transparent a. a. vasculosa. See vascular a. a. ventriculi quart i. The floor of the fourth ventricle of the brain. a. vitellin a. See vitelline a. Colin helm a's. See under Cohnheim. embryonic a. Syn.: germinal a., germinal disk. The a. of an oval thickening or opacity of the central part of the blastoderm, which subsequently becomes the vascular a. It comprises the transparent a. and the opaque a. germinal a. See embryonic a. intercalated a. See non-nucleated a. middle lemniscus a. The median region of the lemniscus, when seen in cro -section, motor a's. See motor centers under center, non-nucleated a. Syn.: intercalated a. The clear spaces sometimes seen between. the endothelial cells of blood ve els, supposed to be due to the removal of portions of the surrounding endothelium. They are smaller than the endothelium and always without nuclei, opaque a. The outer part of the embryonic a., after it has become thickened by the accumulation of formative elements derived from the yolk. transparent a. The thin central part of the embryonic a. of the ovum; so called from its being clear in comparison with the peripheral part, vascular a. The embryonic a. after the primitive blood ve els have formed. vitelline a. The outer surface of the vitelline membrane of the ovum, bordering on the opaque a. [Lat., area, open place.]