Which substance is associated with formation of syndesmoses such as the pubic symphysis?

• A. Collagen
• B. Fibrin
• C. Elastin
• D. Keratin

Answer: (B)

In syndesmoses, bones are joined by dense regular connective tissue that is rich in collagen fibers. This collagenous tissue provides the strong, tightly packed connections that resist pulling apart, as seen in structures like interosseous membranes and the ligaments around the pubic region. The pubic symphysis itself is a fibrocartilaginous joint with a disc between the pubic bones, and the surrounding stabilizing ligaments rely on collagen to maintain stability. Fibrin is a clotting protein involved in wound healing, not in forming these durable bone connections, while elastin offers elasticity in some ligaments and keratin is unrelated to joint structure. Therefore, collagen is the primary substance associated with forming syndesmoses such as the pubic region connections.