Which description best matches the progression of rigor mortis under Nysten's law?

Which description best matches the progression of rigor mortis under Nysten's law?

• A. It progresses from the head down to the body
• B. It progresses from the feet up to the head
• C. It appears simultaneously in all muscle groups
• D. It starts in the torso and moves outward

Answer: (A)

Rigor mortis follows a head-to-toe pattern: it begins in the muscles of the face and neck and then spreads downward through the trunk to the limbs. This downward progression happens because the small, highly active muscles in the head and neck deplete ATP and enter the stiff state first, and the rigidity then migrates to larger muscle groups as time passes. Therefore describing the progression as from the head down to the body best matches Nysten's observation. It does not start in the feet first, nor appear simultaneously in all muscles, nor begin in the torso and radiate outward.

Rigor mortis follows a head-to-toe pattern: it begins in the muscles of the face and neck and then spreads downward through the trunk to the limbs. This downward progression happens because the small, highly active muscles in the head and neck deplete ATP and enter the stiff state first, and the rigidity then migrates to larger muscle groups as time passes. Therefore describing the progression as from the head down to the body best matches Nysten's observation. It does not start in the feet first, nor appear simultaneously in all muscles, nor begin in the torso and radiate outward.