The occipital bone is the trapezoidal-shaped bone found at the lower 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 join together to form the skull and is directly adjacent to five of the cranium bones.
This curved bone houses the foramen magnum, a large oval hole that allows 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, the alar ligaments, and the membrana tectoria. 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 and occipital grow together. The parietals and occipital will fuse together later, between the ages of 26 and 40.