Irregular bones do not fit into the above categories.

Irregular bones serve some special purpose in the body:

Scanner-generated images are sent to a computer to identify specific areas of irregular bone metabolism or abnormal blood flow.

A nutrient canal is found in both long bones and in irregular bones.

Irregular Bones: Protect the central nervous system.

The vertebral column consists of irregular bones.

Irregular bone cells.

They develop through ontogeny, the growth of the individual, as short spines that may fuse along their adjacent margins into larger, irregular bone masses.

The bones of the spine, hips, and some bones of the skull are irregular bones.

They are responsible for the formation of the diaphyses of long bones, short bones and certain parts of irregular bones.

"All bones are of one of four types - lengthy bones, short bones plank or flat bones, and irregular bones."

The five irregular bones of the midfoot-the cuboid, navicular, and three cuneiform bones-form the arches of the foot which serves as a shock absorber.

The irregular bones are bones which, from their peculiar form, cannot be grouped as long bone, short bone, flat bone or sesamoid bone.

Vertebrae (singular: vertebra) are the individual irregular bones that make up the spinal column (aka ischis) - a flexuous and flexible column.

Because fat and muscle often mask irregular bone, they never knew the full extent of a deformity or how they would correct it until they cut through the skin.

These are Long bones, Short bones, Flat bones, Irregular bones, and Sesamoid bones.

In long bones the primary centers occur in the diaphysis/shaft and in irregular bones the primary centers occur usually in the body of the bone.

The irregular bones are: the vertebræ, sacrum, coccyx, temporal, sphenoid, ethmoid, zygomatic, maxilla, mandible, palatine, inferior nasal concha, and hyoid.

Most bones have only one primary center (e.g. all long bones) but some irregular bones such as the os coxa (hip) and vertebrae have multiple primary centers.