Page 140 - كتاب تمريض نسا الاكتروني

138

the birth canal is estimated in relation to the ischial spines, which are inward
projections of the ischium on each side. The ischial spines are smaller and rounder in
shape in the woman’s pelvis than in that of the man.

C-Pubic bones and the symphysis pubis

The pubic bones on either side form the front part of the pelvis. The two pubic bones
meet in the middle at the pubic symphysis. (A symphysis is a very strong bony joint.)
The pubic symphysis is immediately below the hair-covered pubic mound that protects

the woman’s external genitalia.

2-Sacrum
The sacrum is a tapered, wedge-shaped bone at the back of the pelvis, consisting of
five fused vertebrae (the small bones that make up the spinal column or backbone). At

the bottom of the sacrum is a tail-like bony projection called the coccyx? The upper
border of the first vertebra in the sacrum sticks out, and points towards the front of the

body; this protuberance is the sacral promontory — an important landmark for labor
and delivery.

3-Coccyx:

▪ The coccyx consists of four fused vertebrae forming a small triangular bone,

which articulates with the fifth sacral segment

The pelvic canal

The roughly circular space enclosed by the pubic bones at the front, and the ischium on

either side at the back, is called the pelvic canal — the bony passage through which
the fetus must pass. This canal has a curved shape because of the difference in size

between the anterior (front) and posterior (back) borders of the space created by the
pelvic bones. You can see it from the side view in (Figure 2 ).

Table of Content