A textbook of obstetrics . esare united by a triradiate cartilage in the acetabulum, whichbegins to ossify at puberty, the ankylosis being complete in theeighteenth year. The descending ramus of the pubis and the 1 This brief anatomical description of the pelvis is taken, modified, from LeidysAnatomy. 20 PREGXAXCY. ramus of the ischium are also originally united by a cartilagewhich ossifies at about the eighth year. The Anatomy of the Pelvis Obstetrically Considered.—To the obstetrician the pelvis is a canal and not a basin, and is to bestudied mainly in its relation to the fetal body which mu
A textbook of obstetrics . esare united by a triradiate cartilage in the acetabulum, whichbegins to ossify at puberty, the ankylosis being complete in theeighteenth year. The descending ramus of the pubis and the 1 This brief anatomical description of the pelvis is taken, modified, from LeidysAnatomy. 20 PREGXAXCY. ramus of the ischium are also originally united by a cartilagewhich ossifies at about the eighth year. The Anatomy of the Pelvis Obstetrically Considered.—To the obstetrician the pelvis is a canal and not a basin, and is to bestudied mainly in its relation to the fetal body which mustpass through it. The false pelvis is of minor importance, actingsimply as a funnel-shaped structure to direct the presenting parttoward and into the superior strait of the true pelvis. Theobstetrical study of pelvic anatomy may be confined to theshape, size, position, and direction of the true pelvis. Pelvic Shape If one were forced to define the shape of the pelvis he might describe it as a truncated cylinder, but the. Fig. 3.—The shape of the superior strait. description would not be exactly accurate. As a matter of fact,the pelvic canal is of different shape at different levels, and itis necessary to study certain typical planes of the pelvis inorder to understand fully the relationship of fetal to pelvicshape in labor. The first of these imaginary planes is laid atthe entrance to the pelvic cavity or canal, the pelvic inlet orsuperior strait, and is bounded by the promontory of the sacrum,the iliopectineal lines, the crests of the pubis, and the upperedge of the symphysis. The shape of the pelvic inlet is cordi-form. In the bays on either side of the promontory rest theimportant nerve-trunks and blood-vessels of the pelvis, wherethey are guarded from the pressure of the fetal head. It was THE ANATOMY OF THE PELVIS. 21 thought formerly that the shape of the pelvic inlet was elliptical,but this is only exceptionally the case, as in certain justominorpelves, in which the
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
