The occipital bone is the trapezoidal-shaped bone found at the lower-back area of the cranium. The occipital is cupped like a saucer in order to house the back part of the brain. It is one of seven bones that fuse together to form the skull and is directly next to five of the cranium bones.

This curved bone contains the foramen magnum, a large oval hole that allows the medulla oblongata to travel from the brain and connect to the vertebral canal. In addition to the medulla oblongata, the foramen magnum houses the accessory nerves (which provide nerves to the neck and shoulder), the alar ligaments (which help stabilize the head and neck), and the membrana tectoria (a ligament that connects the spine to the occipital bone). This collection allows the brain to communicate with the rest of the body via the spine and aids in rotating the head.

The medulla oblongata also contains the posterior spinal arteries and vertebral arteries, which supply blood to the brain.

As a person ages the occipital bone fuses with other bones of the cranium. Between the ages of 18 and 25 the sphenoid bone, located in the middle of the skull, and occipital grow together. The parietal bones at the top of the head and the occipital bone will fuse together later, between the ages of 26 and 40.