PRESENTATION OF THE VERTEX. 297 



representing only the point of a cone whose base has already es- 

 caped, is expelled by the power of the same effort, and the labor is 

 terminated. 



B. Second Variety. 

 Right occipito-ace tabular position. 

 2d position of Solayres and Baudelocque; right antero-lateral of Madame Coi- 

 vin; right occipito-anterior, Dug6s; 3682 in 20,517 cases, Madame Boivin; 4659 

 in 22,282 cases, Madame Lachapelle. 



733. Admitting that the situation might determine the occurrence 

 of the first variety, the same cannot be said of the second. M. Duges, 

 it is true, mentions two cases, where, in this last named position, the 

 bowel was transposed, being found on the right instead of tlie left, 

 side; but anatomical observations in daily repeated dissections show 

 that auch an anomaly does not occur once in every three or four sub- 

 jects, as ought to be the case were it the only or even the principal 

 cause of the position: and besides, when it has been met with, was 

 it not rather an efiect than a cause; and is it not more rational to at- 

 tribute the second position to the contractions of the womb itselH 

 If it be true, for example, as several facts carefully examined might 

 lead me to believe, that previously to the commencement of labor, 

 the occiput has no determinate position, and does not properly belong 

 to one anterior variety more than to the other, may we not suppose 

 that the uterus, being inclined to the right and in fror-t,is more dis- 

 posed to push the head towards the left than the right side of the 

 pelvis? The impulse received by the foetus in this inclination of the 

 womb is necessarily directed from right to left; in which case the 

 forehead, being arrested by the musculo-vascular edge found in the 

 apex of the triangle represented by the abdominal strait in the living 

 subject, must compel the occiput to yield alone to the movement, 

 and go to place itself opposite the leftilio-pectineal eminence. With- 

 out attaching any great importance to this idea, I should find it an 

 easy task to advance a considerable number of reasons in support of 

 it, and I think it deserving of the attention of those practitioners 

 who love to give an account of what they observe. 



734. However it may be, as to the causes of the right acetabular 

 position, it is twie that its mechanism differs but little from that of 

 the preceding one; the child is impelled by the same power; the 

 head executes the same movements, presents the same circumference 

 in the different planes of the pelvis, and offers the same diameters 

 to the principal diameters and axes of the straits, &c. But the occi- 

 pital fontanel is turned to the right instead of the left; the occipito- 

 bregmatic diameter, instead of proceeding from left to right, goes 



