The human axial skeleton consists of 81 different bones forming the medial core of the body and connects the pelvis to the body, where the appendicular skeleton attaches. As the skeleton grows older the bones get weaker with the exception of the skull. The skull remains strong to protect the brain from injury.

In humans, the axial skeleton serves to protect the brain, spinal cord, heart, and lungs. It also serves as the attachment site for muscles that move the head, neck, and back, and for muscles that act across the shoulder and hip