The infantile uterus is so proportioned that its neck (_collum vel cervix uteri_) constitutes the larger part of the organ, as much indeed as two-thirds. Owing to the small size of the body (_corpus uteri_), the whole uterus is very flat, and its borders ascend in a direction almost parallel to each other, diverging somewhat abruptly into the Fallopian tubes, recalling in some degree the two-horned embryonic form of the organ (_uterus bicornis_). The plicæ palmatæ on the surface of the cervical canal, which make up the arbor vitæ uterina, are strongly developed; the median longitudinal ridge bifurcates, and its divisions can be traced on either side into the uterine orifice of the Fallopian tube (_ostium uterinum tubæ_). The lips of the vaginal portion of the cervix are comparatively speaking very large and terminate in sharp angles. The vaginal mucous membrane is everywhere beset with long papillæ. The development of the uterus shortly before puberty consists chiefly in the enlargement of the body of the uterus, and the growth of its walls in thickness. [Illustration: FIG. 14.—Sagittal section of the female pelvis (after Breiolei). ] At the time of puberty, according to _Toldt_, the body of the uterus in the virgin has already increased till its length is half that of the entire organ; and at the first appearance of menstruation the body and neck of the virgin uterus are nearly equal, with perhaps a slight preponderance in size of the cervix, and the walls of the uterus have become convex. In consequence of this change the organ becomes pear-shaped, and the uterine cavity (_cavum uteri_) assumes the form of a triangle with moderately incurved sides. The cervical canal becomes wider in the middle; the margin of the os uteri becomes smooth and rounded. The walls of the virgin vagina are marked with numerous dentate transverse ridges (_rugæ_), especially near the lower end and on the anterior walls, the columns of the vagina (_columnæ rugarum_), from which the transverse ridges run to either side at right angles, extend half way up the vagina, and are of a hard consistence.