Obstetrics and Pelvis Anatomy

Skeletal System

• Poor posture, beading of the legs, chest deformity, wasted muscles, poor tone, and difficulty in walking can be signs of skeletal system disorders
• Mental confusion, depression, weakness, and sensory deficits can also occur

Pelvis Structure

• The pelvis is made up of four bones: sacrum, coccyx, and two innominate bones
• The sacrum is formed by the fusion of five sacral vertebrae and is triangular in shape
• The sacrum articulates with the coccyx inferiorly and lies between the two innominate bones laterally
• The upper border of the 1st sacral bone forms the sacral promontory, which can reduce the diameter of the pelvic brim if prominent
• The anterior surface of the sacrum is concave and forms the hollow of the sacrum
• Four pairs of foramina are formed where the vertebrae fuse, allowing nerves to pass through and supply the pelvic organs

Sacrum and Coccyx

• The sacrum has a sacral canal that runs longitudinally through the center, forming a passage for spinal nerves
• The coccyx consists of four fused vertebrae and is triangular in shape, articulating with the sacrum above
• The coccyx is of no significance in midwifery

Innominate Bones

• The innominate bones are two and lie on either side of the sacrum
• Each innominate bone has three parts: ilium, ischium, and pubis
• The three parts meet in a cup-shaped depression known as the acetabulum

Ilium, Ischium, and Pubis

• The ilium is the large flared-out part of the innominate bone
• The upper border of the ilium is known as the iliac crest
• The iliac crest terminates anteriorly in the anterior superior iliac spine and posteriorly in the posterior superior iliac spine
• The ilium forms the upper two-fifths of the acetabulum
• The ischium is the lowest portion of the innominate bone and forms the lower two-fifths of the acetabulum
• The ischial tuberosity is the thickened area of bone that forms the body of the ischium
• The pubis is the smaller component of the innominate bone and forms the lower one-fifth of the acetabulum

Test your knowledge of the pelvis anatomy, including the structure and composition of the sacrum, innominate bones, and their significance in midwifery. Learn about the different parts of the pelvis and their functions.