What type of bones are classified as irregular bones?

Irregular bones are characterized by their complex shapes, which do not fit into the other categories of bone classification, such as long, short, or flat bones. Their unique forms are adapted to provide specific support and protection to various organs and structures in the body. For instance, the vertebrae, which are classified as irregular bones, protect the spinal cord and support the structure of the back. Additionally, the pelvic bones and some facial bones also fall into this category due to their intricate shapes and specialized functions.

In contrast, bones that are typically long and thin are known as long bones, which primarily serve as levers in movement. Bones forming the structure of the skull are typically categorized as flat bones, providing protection to the brain. Lastly, bones found in the limbs are generally long bones, designed primarily for mobility and support in locomotion. Thus, the defining feature of irregular bones is their complex shapes and functions, making the choice that describes their characteristics correct.