. An American text-book of obstetrics. For practitioners and students. slater. Coincidently with these changes the general development of the embryohas steadily progressed (Fig. 89), with the result of supplanting the embryonalcharacteristics by those of distinctly fetal type. The head, though propor-tionately large, has become partially once more raised; the boundaries of themouth have become definitely located ; the external parts of the eye, the ear,and the nose are well advanced ; and the general contour of the trunk hasassumed more of the characters of the child. The second month witnesse
. An American text-book of obstetrics. For practitioners and students. slater. Coincidently with these changes the general development of the embryohas steadily progressed (Fig. 89), with the result of supplanting the embryonalcharacteristics by those of distinctly fetal type. The head, though propor-tionately large, has become partially once more raised; the boundaries of themouth have become definitely located ; the external parts of the eye, the ear,and the nose are well advanced ; and the general contour of the trunk hasassumed more of the characters of the child. The second month witnesses the disappearance of the cervical flexion and 100 AMERICAN TEXT-BOOK OF OBSTETRICS. the further lifting of the head, which is still very large (Fig. 90). The faceshows distinct advancement toward its completed type, although the nose is yetunduly broad, and indications of the fissures surrounding the mouth are dis-cernible. The limbs project from the body, and the fingers, including thedifferentiated thumb, and the toes are well defined. By the close of the second. Fig 90.—Human embryo of about eight and a half weeks, enlarged five times (His). month the fetus measures from 25 to 30 millimeters (1 to If inches) in lengthand weighs from 15 to 20 grams. TJie Tliird Month.—The third month establishes the human form, althoughthe head still unduly preponderates. The limbs have acquired their definiteshape, and the imperfect nails are present on both fingers and toes. Duringthis month the external organs of generation become definitely differentiated, PHYSIOLOGY OF PREGNANCY. 101 although they make their appearance several weeks earlier. At the end ofthis period the fetus measures about 7 centimeters (2|- inches) in length andweighs about 120 grams (4 ounces). The Fourth Month.—Short hairs, devoid of pigment, appear on the scalpand on some other parts of the body, which is now covered with firmer skinof rosy hue. The eyelids, nostrils, and lips are closed. The anus opens, and
Size: 1197px × 2088px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
