A textbook of obstetrics . al examination, which shows before- the onset oflabor a high situation of the presenting part ; a flattening ofthe anterior vaginal vault ; a sharp contrast between the smoothoutline of the fetal forehead and the irregular contour of the ABNORMALITIES IN MECHANISM. 371 face. As soon as the os is dilated, the characteristic features ofthe face may be felt. A face presentation has often been mis-taken for a presentation of the breech. The orbital ridges, theeye-sockets, the chin, and, most distinctive of all, the hardgums within the mouth, should enable any one to make
A textbook of obstetrics . al examination, which shows before- the onset oflabor a high situation of the presenting part ; a flattening ofthe anterior vaginal vault ; a sharp contrast between the smoothoutline of the fetal forehead and the irregular contour of the ABNORMALITIES IN MECHANISM. 371 face. As soon as the os is dilated, the characteristic features ofthe face may be felt. A face presentation has often been mis-taken for a presentation of the breech. The orbital ridges, theeye-sockets, the chin, and, most distinctive of all, the hardgums within the mouth, should enable any one to make thedifferential diagnosis. This presentation should be consideredas a pathological one, for it entails great danger upon bothmother and child. The causes of face presentations are divided under three heads,as follows: (1) Conditions preventing flexion, as tumors of theneck ; increased size of the thorax ; constriction of the cervixabout the neck ; coiling of the cord around the neck ; toniccontraction of the neck Fig. •Face presentation. Delivery of the face. (2) Conditions favoring extension, as mobility of the fetus ;oblique position of the child and uterus, especially when theabdominal surface of the child is directed downward and thepelvis is flat ; a dolichocephalic head, in which the posteriorsegment of the skull is longer than the anterior ; tumors uponthe back, as spinal meningocele. Causes which promote exten-sion of the trunk and shoulders, and consequently of the head,as an overfilled bladder of the mother pressing upon the childsback. After the head has descended into the pelvic cavity, the 372 THE MECHANISM OF LABOR. face presentation may be duo to the conversion of an occipito-posterior position into that of the face, as already described. (3) Anything that interferes with the normal engagement ofthe head in the pelvis, as overgrowth of the fetus, deformedpelvis, pelvic tumor. The Mechanism.— The successive steps of the mechanism oflabor in a face p
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Keywords: ., bookcentury1800, bookdecade1890, bookidtex, booksubjectobstetrics
