space

Continuous extension in the three dimensions of length, breadth, and thickne ; in a popular restricted sense, room, empty or vacant s. air s. Syn.: air chamber. 1. Space in cubic feet nece ary for each person in a hospital, jail, etc. 2. An accumulation of air at the rounded end of an egg, between the middle and internal fibrous envelopes, which penetrates through the shell to replace a certain amount of the watery material of the egg lost by evaporation, anterior mediastinal s. A s. directed obliquely from above downward and to the left of the median line, anterior perforated s. A triangular s. on the lower surface of each cerebral hemisphere, bounded anteriorly by the three roots of the olfactory nerve, posteriorly by the optic tract, and externally by the beginning of the sylvian fi ure, arachnoid s. See subarachnoid lymph s. and subdural s. cir cum vascular lymph s's. Tubes surrounding blood ve els and communicating with true lymphatic ve els, cir cum vascular s. See cell s., under cell, havers i an s's. Irregular spaces found especially in growing bones. They have jagged outlines, and appear to be the result of the absorption of compact bone. Such a s. may become filled by the development of havers i an systems within it. inter arytenoid s. The s. between the arytenoid cartilages behind the proce us vocales. intercellular s's. Minute s's between the intercellular apophyses of prickle cells. They are cro ed by the intercellular bridges. intercostal s's. S's between adjacent ribs, inter mesoblastic s's. Cavities, one on each side, included between the parietal and the visceral laminae of the lateral mesoblastic plates of the embryo, inter metatarsal s's. S's between the metatarsal bones. inter peduncular s. Syn.: cisterna chiasmatic a. A diamond-shaped cavity at the base of the brain, bounded anteriorly by the optic tracts and posteriorly by the crura cerebri. It contains the tuber cinereum, infundibulum, pituitary body, and corpora albicantia. lateral perforated s. A lamina of white substance perforated with numerous apertures, seen at the bottom of the fi ure of Sylvius, lymph s. A cleft or s. in the ti ues or in lymphatic glands containing or giving pa age to lymph. See lymph sinuses, under sinus. mediastinal s. The cavum mediastinum (see under mediastinum), pelvirectal s. See ischiorectal fo a, under fo a, perforated s. See anterior perforated s., lateral perforated s., and posterior perforated s. per i choroidal s. A lymph s. between the choroid and the sclerotic. per i vascular s. See cir cum vascular lymph s's. placental blood s's. See inter villous lacunae, under lacuna, pleuroperitoneal s's. See inter mesoblastic s's. popliteal s. A s. on the posterior surface of the knee bounded by the hamstring tendons and the heads of the gastrocnemius, posterior mediastinal s. An irregular triangular s., running parallel with the vertebral column, posterior perforated s. A small ma of gray matter near the center of the lower surface of the brain. It is a -portion of the floor of the third ventricle, and is pierced by numerous small ve els which supply the optic thalami. posterior triangular s. A s. bounded by the posterior border of the sternocleidomastoideus, the upper border of the clavicle, and the anterior border of the trapezius and occiput, pre vesical s. The s. between the transversal is fascia and the posterior surfaces of the recti abdominis below the semicircular line of Douglas. retroperitoneal s. The s. posterior to the peritoneum and in front of the spinal column and the muscles of the lumbar region, semilunar s. See Traube's s., under Traube. s's of Fontana. Cavities between the proce es of the lig amentum pectin a tum irid is communicating with the anterior chamber of the eye. s's of His. See cir cum vascular s's. s. of Tenon. A lymph s. between the fascia of Tenon and the sclerotic, subarachnoid lymph s. The interval between the arachnoid and the pia. That of the spinal cord and the brain are continuous and communicate with the ventricles of the brain by the foramen of Monro, the cir cum vascular s's of the brain, and the perineurium, subdural s. The s. between the dura and the arachnoid, sub vaginal s. A lymph s. within the sheath of the optic nerve. Traube's semilunar s. See Traube. uterorectal s. The pouch of Douglas. ute roves i cal s. The vesico-uterine fo a, visual s. The s. contained within the visual field, yolk s. The s. left between the vitellus and the zona pellucid a by a retraction of the vitellus at that point. Into this s. are expelled the extrusion globules. [Lat., spatium.l