A manual of obstetrics . osterior. Most commonly it is the right obliquediameter that is involved, and generally the occiput is ante-rior. The transverse diameter of the superior strait beingthe largest, Spiegelberg has found that in per cent, ofall vertex presentations the head enters the strait in thisdiameter, but that under the action of the resistant pelvicwalls it soon comes to occupy one or other of the fourpositions of the vertex. In the balance of the cases theentrance into the pelvis will be primarily in one of the ob-lique diameters; this position is termed Solayres obliquityof
A manual of obstetrics . osterior. Most commonly it is the right obliquediameter that is involved, and generally the occiput is ante-rior. The transverse diameter of the superior strait beingthe largest, Spiegelberg has found that in per cent, ofall vertex presentations the head enters the strait in thisdiameter, but that under the action of the resistant pelvicwalls it soon comes to occupy one or other of the fourpositions of the vertex. In the balance of the cases theentrance into the pelvis will be primarily in one of the ob-lique diameters; this position is termed Solayres obliquityof the head. The positions of the vertex are as follows:(i) The occiput anterior and to the left—left occipito-anterior; symbol, L. O. A.; (2) the occiput anterior and tothe right—right occipitoanterior; symbol, R. O. A.; (3) theocciput posterior and to the right—right occipitoposterior;symbol, R. O. P.; (4) the occiput posterior and to the left—left occipitoposterior; symbol, L. O. P. EUTOCIA, OR NORMAL LABOR. 137. Mechanism of the First Position.—Left occipitoanterior—L. O. A. (Fig. 57).—About 70 per cent, of all vertex casespresent in this position. Cause.—Thereason for this great frequency maybe found, in the first place, in theposition of the rectum to the left sideof the pelvis; this, by cutting offa portion of the left oblique diam-eter of the pelvis, makes it smallerthan the right, in which diameter thefetus accordingly finds more roomfor growth and descent. In the sec-ond place, the prominence affordedby the anterior curvature of the ma-ternal spinal column renders an ante-rior position of the rigid fetal backmore conducive to the comfort of thefetus. Diagnosis.— Vaginal examina-tion shows that the depressed occiputand smaller fontanel are anterior andpointing toward the left iliopectinealeminence. The sagittal suture runsfrom the small fontanel obliquelybackward and to the right in the line of the right obliquediameter. The head holding a position in t
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
