Final answer:
A small or non-prominent back of the skull is often due to a less pronounced external occipital protuberance. This area and the other structures of the posterior skull play roles in attachment and support. The formation and development of these features can influence the overall prominence of the skull's back.
Step-by-step explanation:
For individuals with a small, non-prominent back of the skull, it's typically characteristic for the external occipital protuberance to be less pronounced. The external occipital protuberance is a small bump located at the midline on the posterior skull, serving as an attachment site for ligaments of the posterior neck. In contrast, infants have softer and less developed skulls with areas called fontanels, which are soft spots that allow for the movement and deformation of the skull bones during birth. The posterior fontanel is located at the back of the head and usually closes as the skull bones ossify post-birth. The occipital bone, which forms the posterior skull, contains the foramen magnum and is flanked by occipital condyles that form joints with the cervical vertebrae, supporting the skull.
The skull's anatomy in the posterior view shows various attachment sites for muscles and joints involved in supporting the skull. If these areas are underdeveloped or not prominent, it may result in a smaller looking back of the head. Foramen spinosum, articular tubercles, and other features also contribute to the shape and structure of the skull but predominantly deal with the entry points for arteries or articulation with other bones, such as the mandibular fossa with the mandible.