Webster
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Webster’s Revised Unabridged Dictionary · 1913

Vertebra

Ver′te·bra, n.; pl. Vertebræ (#). [L. vertebra, fr. vertere to turn, change. See Verse.]

1. (Anat.) One of the serial segments of the spinal column.

☞ In many fishes the vertebræ are simple cartilaginous disks or short cylinders, but in the higher vertebrates they are composed of many parts, and the vertebræ in different portions of the same column vary very greatly. A well-developed vertebra usually consists of a more or less cylindrical and solid body, or centrum, which is surmounted dorsally by an arch, leaving an opening which forms a part of the canal containing the spinal cord. From this dorsal, or neural, arch spring various processes, or apophyses, which have received special names: a dorsal, or neural, spine, spinous process, or neurapophysis, on the middle of the arch; two anterior and two posterior articular processes, or zygapophyses; and one or two transverse processes on each side. In those vertebræ which bear well-developed ribs, a tubercle near the end of the rib articulates at a tubercular facet on the transverse process (diapophysis), while the end, or head, of the rib articulates at a more ventral capitular facet which is sometimes developed into a second, or ventral, transverse process (parapophysis). In vertebrates with well-developed hind limbs, the spinal column is divided into five regions in each of which the vertebræ are specially designated: those vertebræ in front of, or anterior to, the first vertebra which bears ribs connected with the sternum are cervical; all those which bear ribs and are back of the cervicals are dorsal; the one or more directly supporting the pelvis are sacral and form the sacrum; those between the sacral and dorsal are lumbar; and all those back of the sacral are caudal, or coccygeal. In man there are seven cervical vertebræ, twelve dorsal, five lumbar, five sacral, and usually four, but sometimes five and rarely three, coccygeal.

2. (Zoöl.) One of the central ossicles in each joint of the arms of an ophiuran.

Webster’s Revised Unabridged Dictionary, Noah Porter, editor (Springfield, Mass.: G. & C. Merriam, 1913). Public domain. Text as transcribed by MICRA, Inc., from Project Gutenberg. Changed for Deep Dive Bible: Greek, which our source spelled in Latin letters, set in Greek letters; entries of one spelling merged into one article; Greek words our source left out (shown as “?”), read from the 1898 printing, from the same plates (the Library of Congress’s copy), where the place could be found with certainty. Of the others, 1,362 (a word or a single letter each) were inferred by AI from the context by the dictionary’s own rules and are marked with a wavy underline (tap or point at one to see the note); the rest, which could not be inferred with confidence, are left as “?”.