ventric'ulus, pi. veniric'uli

[L. dim. of venter, belly.] [BNA] I. The stomach. 2. A ventricle, as of the brain or heart, v. dex'ter [BNA], right ventricle of the heart, the cavity on the right side of the heart which receives the venous blood from the right atrium and drives it by the contraction of its walls into the pulmonary artery. V. laryn'gis [B NA], sinus laryngis, the rece in each lateral wall of the larynx between the false and true vocal cords, v. later a'lis [BNA], lateral ventricle, a cavity in the interior of each cerebral hemisphere, communicating through the foramen of Monro with the third ventricle; it has four indistinctly separated parts, the pars central is (cella media) and three cornua anterior, posterior, and inferior or descending. T. quar'tus [BNA], fourth ventricle, a cavity of roughly rhomboidal shape in the brain, the floor, or anterior wall, of which is formed by the dorsal surface of the pons and medulla; it is continuous below with the central canal of the spinal cord, anteriorly with the aqueduct of Sylvius. V. quin'tus, fifth ventricle, cavum* sept i pellucid i [BNA). v. sin is'ter [BNA], the left ventricle of the heart, the cavity on the left side of the heart which receives the arterial blood from the left atrium and drives it by the contraction of its walls into the aorta, v. term in a'lis [BNA], the dilated portion of the central canal of the spinal cord at the tip of the conus medullar is. v. ter'tius [BNA], third ventricle of the brain, a narrow cavity between the two optic thalami, extending from the lamina cinerea to the pineal body; its floor is formed by the tuber cinereum, the corpora mamillar i a, the subs tanti a per for at a posterior, and a portion of the tegmenta of the pedunculi cerebri; its root is formed by a fold of pia mater (velum inter pos i tum) lined by a thin epithelial layer attached to the tasnia thalami on either side.