Final answer:
The occipital bone forms the posterior skull and base of the cranial cavity, and includes the external occipital protuberance and the foramen magnum. It forms joints with the first cervical vertebra via the occipital condyles.
Step-by-step explanation:
The occipital bone in the skull contributes to the formation of the posterior part of the skull and base of the cranial cavity. Key structures of the occipital bone include the external occipital protuberance, which serves as an attachment site for neck ligaments, and the occipital condyles, which form joints with the first cervical vertebra. The occipital bone also contains the foramen magnum, a large opening that allows for the passage of the spinal cord as it exits the skull. When discussing the developmental aspect, the basioccipital, exoccipital, and supraoccipital are all embryological parts that contribute to the formation of the adult occipital bone.