VERTEBRA

(Lat.), n. f. Vu6rt(weart)'eab-ra3. From vertere, to turn. Gr., tr^oVfivAo?, <rir6v \os. Fr., vertebre. Ger., Wirbel. 1. One of the o eous segments of which the " skeleton proper " is made up. It consists typically of a number of o eous pieces definitely arranged so as to form two rings, a dorsal and a ventral, meeting in a common centre (the centrum), which inclose respectively the central nervous system and the circulatory organs and vis Viewed from above. ^ Viewed laterally THE SEVENTH CERVICAL VERTEBRA. cera, and are known as the neural and hasmal arches (q. v.). 2. As commonly used, one of the separate pieces which make up the vertebral column. [L.] A mph i cos lous v. [Huxley]. A v. of which the body is concave both before and behind. Cf. Proccelous v. and Opisthoccelous v. Basilar v. The last lumbar v. Caudal vertebrae. 1. The vertebrae of the tail. [L. 41 (a, 14).] 2. In man, see Coccygeal vertebrae. Cephalic vertebrae. Ger., Kopfwirbel. The bones of the skull considered as vertebral in type. Some writers restrict the term to such of the cranial bones as are developed from primordial cartilage, excluding those of intra-membranous formation. Cf. Cranial vertebrae. Cervical vertebrae. The anterior or superior seven of the vertebras, the two nearest the skull being termed the atlas and axis. They have the transverse proce es perforated for the vertebral artery, the spinous proce short and bifid and the lumen of the neural arch somewhat triangular and larger than in the dorsal or lumbar vertebrae. [L.] Coccygeal vertebrae. Ger., Stei wirbel. Syn.: caudal vertebrae. The vertebrae of the coccygeal region. They are rudimentary, commonly four in number, sometimes five, seldom three. Cranial vertebrae. Ger., Schadelwirbel. Vertebras whose component parts consist of cranial bones and the o eous and cartilaginous appendages of the skull. The theory of their existence was advanced by Goethe and Oken and elaborated by Cuvier and Sir Richard Owen. Their homology with true vertebras is no longer accepted on embryological evidence. [L.] Dorsal vertebrae. The vertebrae, twelve in number, with which the ribs articulate. They are especially characterized by articular surfaces for the ribs, downward-sloping spinous proce es, and a small circular lumen of the neural arch. [L.] False vertebrae. The fused segments of the coccyx and the sacrum. Ua, blue; Us. lull; U4. full; U5, urn; U, like ii (German). [s. 709]