Which joint is classified as a synarthrodial joint?

A synarthrodial joint is a type of joint that is characterized by its immovable nature. This classification is important in understanding how different joints function within the human body. The coronal suture, which is found in the skull, serves as an excellent example of a synarthrodial joint. It connects the frontal bone to the parietal bones, providing structural integrity and protection to the brain. The bones involved in sutures are tightly interlocked and connected by a thin layer of fibrous tissue, preventing any movement, which is indicative of a synarthrodial joint.

In contrast, other joints listed have different classifications. The proximal radioulnar joint allows for rotational movement of the radius around the ulna, thus functioning as a pivot joint. The sacroiliac joint supports weight transfer between the upper body and the lower limbs and allows for limited motion, making it a synovial joint. Similarly, the pubic symphysis, which is located between the pubic bones, is a cartilaginous joint that permits slight movement during activities such as walking and childbirth. Understanding these classifications helps clarify the functional diversity of joints in the body.