The pelvis is indeed classified as an irregular bone. Irregular bones are bones that do not fit into the categories of long, short, or flat bones. They often have complex shapes that are not easily categorized.
The pelvis is made up of several bones, including the sacrum, coccyx, and the two hip bones (each consisting of the ilium, ischium, and pubis). These bones are fused together in adults, forming a complex structure that supports the spine and protects the pelvic organs.
Irregular bones, like the pelvis, serve various functions such as providing structural support, protecting internal organs, and offering attachment points for muscles. The pelvis, in particular, plays a crucial role in supporting the weight of the upper body when sitting and standing, and it also forms the birth canal in females.