Fibrous (synarthroses) joints are formed by fibrous connective tissue and include which of the following?

• A. Sutures of skull bones
• B. Intervertebral discs
• C. Knee joints
• D. Symphysis pubis

Answer: (A)

Fibrous joints are joined by dense fibrous connective tissue and usually have no joint cavity, producing little to no movement (synarthroses). The classic example is the sutures between skull bones. These sutures consist of tight fibrous tissue that binds the cranial bones together and interlocks them, which is why they’re immovable in adults and mainly allow growth during early life.

Intervertebral discs are not fibrous joints; they’re cartilaginous joints made of fibrocartilage (a symphysis) that allow a small amount of movement. Knee joints are synovial joints with a joint cavity, articular cartilage, and a synovial lining, designed for mobility. The pubic symphysis is another cartilaginous joint (a secondary cartilaginous joint) formed by fibrocartilage, offering limited movement rather than being a fibrous, immobile connection. So the skull sutures fit the definition of fibrous synarthroses.