Which joint is an example of fibrous structure allowing little to zero movement?

The cranial sutures are a prime example of a fibrous joint structure that allows little to zero movement. These joints are formed by the edges of the bones in the skull, which are tightly bound together by fibrous connective tissue. This immobile configuration is crucial for protecting the brain and maintaining the integrity of the skull as it serves as a rigid casing.

In contrast, the vertebrae are examples of cartilaginous joints, which permit more movement due to the intervertebral discs located between them that provide flexibility and cushioning. The base of the thumb involves a saddle joint, which allows a broader range of motion than immobile joints. The elbow, as a hinge joint, allows bending and straightening, demonstrating significant movement. Therefore, the cranial sutures remain distinct as the correct answer by virtue of their structure that maintains stability rather than allowing movement.