VENTRICLE

n. Veant'ri2-k'l. Lat., ventriculus (dim. of venter, the belly). Fr., ventricule. Ger., Ventrikel, Kammer. A small thick-walled cavity in an organ, especially the heart or brain. Anterior v's. See Lateral v's. Anterior v. of the heart. See Right v. of the heart. Aortic v. See Left v. of the heart. Cerebellar v. [Owen]. A prolongation of the fourth v. into the primary cephaHc vesicle; described as strictly embryonic in man, but persistent in birds, fishes, and reptiles. [I, 14 (K).] Cerebral v. A v. of the brain. Fifth v., First v. [Wenzel]. Lat., sinus quint us. Ger., Kammer der Scheidewand. The space between the two laminae of the saeptum lucidum. [L.] Fourth v. Lat., ventriculus cerebri quart us. Ger., Kammer des kleinen Hirns. A lozenge-shaped space bounded laterally above by the proce us e cerebello ad testes and below by the posterior pyramids and the restiform bodies. Its floor is formed by the posterior surface of the pons Varolii and medulla oblong at a, and its roof by the valve of Vieu ens and the inferior surface of the cerebellum (a layer of the pia being interposed). It connects above with the aqueduct of Sylvius, and below with the central canal of the spinal cord. [L, 31, 172, 332.] Large v's, Lateral v's (of the brain). Lat., ventriculi cerebri later a les. Ger., Seitenventrikel des Gehirns. Serous cavities, one on each side, in the cerebral hemispheres, lined with ciliated epithelium, and separated from each other in the middle line by the saeptum lucidum. They communicate with the anterior portion of the third v. and with each other by the foramen of Monro. Each is divided into a central triangular portion, the body, from which the anterior, middle, and posterior cornua descend into the substance of the hemisphere. The roof is formed by the lower surface of the corpus callosum and the substance of the cerebrum, and the floor by the corpus striatum, ttenia semicircular is, optic thalamus, chorioid plexus, corpus flmbriatum, fornix, cornu Ammonis, eminent i a collateral is, fascia dentata, and the substance of the cerebrum. [L, 142, 172, 332.] Lateral v. of the cerebellum. A furrow on the floor of each half of the fourth v. near the lateral wall. [I, 35 (K).] Left v. of the heart. Lat., ventriculus cord is sinister. Ger., linker Ventrikel. The cavity which occupies a small part of the left anterior portion of the heart and the larger part of its left posterior portion, and forms the apex. It communicates with the aorta and the left auricle. By the contractions of its walls it propels the arterial blood into the arterial system through the aorta. [L-] Middle v. See Third w. Middle v. of the cerebellum. The median fi ure on the floor of the fourth v. [I, 35 (K).] Optic v's. See Lateral v's. Pineal v. Of Leuret and Gratiolet, a small cavity in the centre of the pineal gland. [I, 35 (K).] Posterior v. of the heart. See Left v. of the heart. Prosencephalic v. [Owen]. A lateral v. in the brain of the embryo. [I, 14 (K).] Right v. of the heart. Lat., ventriculus cord is dexter. Ger., rechter Ventrikel. The rounded triangular cavity of the heart which forms the greater part of its anterior and a small part of its posterior portion. It communicates with the right auricle, and propels the venous blood through the pulmonary arteries. [L.] Second v's, Superior v's. See Lateral v's. Sylvia i i v. See Fifth v. Terminal v. See Fourth v. Third v. Ger., Mittelhirnhohle, mittlere Kammer. An open space between the optic thalami, bounded above by the lower surface of the velum inter pos i tum, and laterally by the peduncles of the pineal gland. Its floor is formed by the lamina cinerea, tuber cinereum, infundibulum, corpora albicantia, and posterior perforated space. It communicates with the lateral v's through the foramen of Monro, and with the fourth v. through the aqueduct of Sylvius and with the cavity of the infundibulum. [L, 31, 142, 172.] Third v. proper. The third v. as distinguished from the foramen of Monro. [" Boston Med. and Surg. Jour.," Aug. 12, 1880, p. 152 (K).] V. of Aranti us. 1. The small depre ion or cavity at the pointed extremity of the calamus script or i us. [I, 17 (K).] 2. See CALAMUS script or i us.V. of Morgagni. See V. of the larynx. V. of the corpus callosum. See Fifth v. V's of the heart. The right and left v's of the heart. V. of the larynx. Lat., sinus laryngis. An elongated depre ion between the superior and inferior vocal O, no; Oa, not; O3, whole; Th, thin; Tha, the, U, like oo in too; 380 [s. 703]