SEGMENT

n. Seag'm'nt. Lat., segmentum (from secare, to cut). Fr., s., segmen. Ger., S., Abschnitt. 1. A part separated more or le completely from other parts, [a, 48.] 2. In botany, a division of a lobed or cleft leaf or other plant organ. When there are subdivisions, the s. is the primary division, and its parts are called lobes, [a, 35.] Interanmilar (nerve') s. See INTERNODE of Ran vier. Intermediate s. of a cilium. Ger., Zwisclienglied. A soft, isotropous, faintly striated portion of a cilium intervening between the pedicle and the cilium proper. [Engelmann, ' Arch. f. Physiol.,'1 1880, p. 505 (J).] Lower s. of the uterus. In an obstetrical sense, that portion of the organ which stretches and dilates during labor, but does not take part in the work of expelling the ovum; being all that portion situated below the ring of Band). [Lahs, " Arch. f. Gyn.," xxiii, 2; "Med. Times and Gaz.," Apr. 11, 1885, p. 490.] Medullary s's. Fr.,s's cylindriques. G?r.,Marks'e, Einkerbungen, Faserglicder, Hohlcylindtr. Lan term ann's che Gliederungen. S's or divisions in the medullary sheath of a nerve fibre, formed by the oblique markings or incisures of Schmidt. The s's have solid or hollow conical ends, and fit together like funnels. The s's in an internode of Ranvier are variable in length and in number, and are supposed by some to be due to manipulation, while others believe them to be normal. [J. 10, 30, 31.] Pubic s. of the pelvic floor [D B. Hart]. The upper and anterior of the two overlapping s's into which Hart divides the pelvic floor in women. It " consists of what extends from symphysis pubis to anterior vaginal wall, inclusive of the latter, and is chiefly made up of bladder." [A, 48.] Rivinian s. of the tympanic ring. The anterior superior groovele s. lying between the two points of attachmnt of the tympanic portion of the temporal bone to its squamous portion. [F.] Sacral s. of the pelvic floor [D. B. Hart]. The lower and posterior of Hart's two s's of the pelvic floor in women. It " extends from sacrum to posterior vaginal wall." [A, 48.] Cf. Pubic s. of the pelvic floor. S. de Hand 1 (Fr.). See BandVs RING. S's de la trachee (Fr.). See Trachenl RINGS. S's du noyau lenticulaire(Fr.). The zones of the lenticular nucleus. [I, 55 (K).] S's of l.:mt iTtn:i mi. See Medullary s's. Yolk s. See Segmentation CELL. Zwilluiig 'e (Ger.). See Cleft nuclear FILAMENTS. [s. 468]