Irregular bones are a category of bones that do not fit into the standard classifications of long, short, or flat bones. They have complex shapes that provide support and protection to various body structures. Examples of irregular bones include the vertebrae in the spine and the pelvic bones. These bones are composed of a mix of compact and spongy bone tissue, allowing them to withstand stress and provide flexibility. Irregular bones play essential roles in the body, such as protecting the spinal cord and supporting the weight of the upper body.