Twenty-one of those pieces are fused together by sutures, which are nearly rigid, fibrous joints found only in the skull. Similar connective fibers are found in teeth and the spine. These sutures give the appearance of cracks or fissures.

Do our skulls have cracks?

The cranium, the part of the skull above and behind the face, includes eight bones that come together at special joints called sutures (SOO-churs). These are the bones that crack or break when someone has a skull fracture.

Why is there cracks in the skull?

A skull fracture occurs when a force that's strong enough to break the bone hits the skull. Any type of impact to the head can cause a skull fracture. This includes being hit with an object, falling and hitting the ground, injuring the head in a car accident, or any other type of trauma.