The principles and practice of obstetric medicine and surgery : in reference to the process of parturition / by Franics H. Ramsbotham.
- Francis Henry Ramsbotham
- Date:
- 1865
Licence: Public Domain Mark
Credit: The principles and practice of obstetric medicine and surgery : in reference to the process of parturition / by Franics H. Ramsbotham. Source: Wellcome Collection.
Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.
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![cut. a, e,f. b, being right anterior inclined plane, >■./, ■ •, </, being right r >s- terior inclined plane. The anterior inclined piano is made up on either Bide of a part of the ilium, the plane of the ischium, insertions of the Bacro-eciatio ligaments, tuberosity of the ischia, rami of the pubis and ischium, symphysis pubis ami foramen obturator. The posterior inolined plane is made up of the origin of the Bacro-eciatio ligaments, the saoro- sciatio foramina, and the half of the hollow of the sacrum ami coccyx. In whatever manner these planes may he formed, their direction is always found to lie the same: thus, the anterior inclined planes look from without, inwards; from above, downwards; and from behind, forwards: the look from without, inwards; from above, downwards; and from forward, backwards: they therefore resemble the four sides of a trapezium. The anterior inclined plane is longer than the posterior. During parturi- tion, the two extremities id* the child's head always glide upon two of these four planes, and the two are always diagonally opposite. It seems evident that it is to the peculiar form of these inclined planes, that we owe that stage of the mechanism of labour, called Rotation; for, let anyone try the experiment of throwing a round body, such as a billiard ball, upon one of these planes, it will invariably be found to move in a line, coinciding with the inclination of that plane. We are aware that it occasionally happens, that rotation dues not take place; and, in fact, the head is delivered without the performance of Ige of labour. Hut these cases are the exceptions, and result from the extreme small- the head in comparison with the pelvis, the disproportion being such as not to require ! load !•/ abut against any portion of the pelvis.] TllK OUTLET is also inclining to an oval '•lit it i< even <>f greater irregularity than the brim, owing principally to the projec- tion of the tip <>f the coccyx behind, ami to the large BinuoeitV in front, the arch of the _ fig. - ; and :!, fig. •_', a, b). In extent the diameters of the outlet are nearly the same as at the brim ; in situation they are i. Thus the long diameter is from be- fore backward-, in a line extending from the point of the coccyx to the under edge of the symphysis pubis (plate :'-, ti_'. 2, a); and when the boi • i-. in labour, this mea- sures five inches or more; although, in the or- dinary state of the parts, the extremity being directed forwar i stent is only four. The short diameter extends laterally, from the tuberosity of one ischium to that of the other, is incapable of being increased, and measure* four (b).](https://iiif.wellcomecollection.org/image/b21007123_0039.jp2/full/800%2C/0/default.jpg)
