Following Nysten's Law, how does rigor mortis progress?

Following Nysten's Law, how does rigor mortis progress?

• A. From the head down to the body
• B. From the feet up to the head
• C. From the center outward
• D. In random areas

Answer: (A)

Rigor mortis follows a head-to-toe pattern. After death, muscles lose ATP, causing actin–myosin cross-bridges to stay formed and the muscles to stiffen. The smallest, most active muscles—starting with the face and jaw—go first, then the stiffness spreads downward to the neck, trunk, and finally the limbs. That cranial-to-caudal progression is the hallmark described by Nysten's Law, so the correct understanding is that rigor mortis progresses from the head down to the body. Patterns like starting at the feet, starting at the center, or appearing in random areas don’t match this observed sequence.

Rigor mortis follows a head-to-toe pattern. After death, muscles lose ATP, causing actin–myosin cross-bridges to stay formed and the muscles to stiffen. The smallest, most active muscles—starting with the face and jaw—go first, then the stiffness spreads downward to the neck, trunk, and finally the limbs. That cranial-to-caudal progression is the hallmark described by Nysten's Law, so the correct understanding is that rigor mortis progresses from the head down to the body. Patterns like starting at the feet, starting at the center, or appearing in random areas don’t match this observed sequence.