What is the principal material making up the connections between skull joints?

The principal material making up the connections between the joints of the skull is sutures. Sutures are specialized fibrous joints that serve to connect the bones of the skull. They are made up of dense connective tissue that provides stability and allows for minimal movement, which is essential for protecting the brain and maintaining the structural integrity of the skull.

Sutures not only hold the bones of the skull together, but they also contribute to the overall architecture of the cranial structure, facilitating the growth of the skull in response to the developing brain during infancy and early childhood. Over time, sutures may ossify, becoming immovable as a person matures, but they play a crucial role throughout a person's early life.

The other options represent different types of connective tissues or structures found in the body, but they do not play the same role in connecting the bones of the skull. Cartilage serves as a smooth surface on the joints elsewhere in the body; ligaments connect bone to bone in various other joints; and tendons attach muscles to bones. However, their functions and locations are distinct from the sutures that specifically connect skull bones.