INCLINATION OF THE PELVIS. 



99 



The axis of the pelvis is the name given to a line drawn in the middle 

 at right angles to the planes of the brim, cavity and outlet. The posterior 

 wall, formed by the sacrum and coccyx, being about five inches long and 



Fig. 91. 



Fig. 92. 



Fig. 91. VERTICAL ANTERO- 

 POSTERIOR SECTION OP A 

 FEMALE PELVIS, MADK 

 THROUGH THE SYMPHYSIS 

 PtJBIS AND MIDDLE OF 

 THE SACRUM AND COCCYX, 

 SHOWING THE LEFT LATERAL 

 HALF (reduced from Na- 

 gele's figure), 



1, symphysis pubis ; 2, 

 base of the sacrum and pro- 

 montory ; 3, coccygeal bones ; 

 4, anterior superior spine 

 of ilium; 5, tuberosity of 

 ischium ; 6, spine of ischium 

 (the obturator foramen is not 

 represented so pointed below 

 as it generally is in females). 

 The vertical and horizontal 

 lines in the lower part of the 

 figure serve as standards of 

 comparison for the degree of 

 inclination of the pelvis, as 

 illustrated by the next 

 figure. 



Fig. 92. SKETCH OF PART OF THE 

 PRECEDING FIGURE, SHOWING 

 THE INCLINATION OF THE BRIM 



OF THE PELVIS AND ITS AXIS 



IN THE ERECT POSTURE. 



a, &, line of inclination of the 

 brim of the true pelvis from 

 above the symphysis pubis to the 

 promontory of the sacrum ; e, f, 

 a line inclining backwards and 

 upwards, touching the lower edge 

 of the symphysis pubis and point 

 of the coccyx ; c, d, axis of the 

 brim at right angles to the plane 

 of the brim ; from d to the dotted 

 line at right angles to e f, curved 

 axis of the cavity continued into 

 that of the outlet of the osseous 

 pelvis ; h, g, axis of the outlet 

 of the pelvis when the soft parts 

 are combined. 



concave, while the anterior 

 wall at the symphysis pubis 

 is only one and a half or 

 two inches long, the axis is 

 curved : it is directed at the inlet upwards and forwards towards the um- 

 bilicus, and at the outlet downwards and a little forwards. The curvature 

 of the axis of the pelvis is specially important as indicating the course 

 in which the child's head is propelled in the process of parturition ; and 

 it may be mentioned that in the female pelvis with the soft parts entire, the 

 axis of the outlet is curved much more forwards than in the skeleton, the 



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