Final answer:
The external occipital protuberance is a small bump on the occipital bone. It serves as an attachment site for neck ligaments and supports the skull on top of the vertebral column. The protuberance on the occipital bone is most likely less than 90 degrees.
Step-by-step explanation:
The rough skull with a protuberance on the occipital bone is a common anatomical feature called the external occipital protuberance. It is a small bump located at the midline on the posterior skull. In this case, the protuberance on the occipital bone is most likely less than 90 degrees.
The occipital bone forms the posterior skull and posterior base of the cranial cavity. It contains a large opening called the foramen magnum, oval-shaped occipital condyles, and serves as an attachment site for neck ligaments. The occipital bone supports the skull on top of the vertebral column.