Читать книгу Mother, Nurse and Infant - S. P. Sackett - Страница 23

There is considerable difference between the male and female pelvis, in shape and size. The pelvis in the male is smaller but deeper; the bones are thicker and the brim is more circular, the depth of the symphasis pubis is greater, the sacrum is more perpendicular, the arch of the pubis is narrower, the tuber ischii are nearer each other, and the coccyx less movable. In the female the iliac fossæ are larger, the interval separating the angle of the pubis from the acetabulum is greater, causing the prominence of the hips and wider separation of the thighs, the superior straight is larger and more elliptical, the curve of the sacrum deeper and more regular, the tuberosities of the ischii are further apart, and the arch of the pubis broader. From the greater width of the female pelvis, and from the upper end of the thigh bones being farther apart than in the male, the thigh bones approach each other in their descent, giving a peculiarity to the movements of the female in walking.

The soft parts lining the pelvis and covering it externally modify the diameters of the pelvis, but the effect of these additions in diminishing the internal diameter is not very great. The diameter of the cavity is lessened thereby from one-fourth to one-half an inch.