What is the Meryon/Slip through sign described in Duchenne muscular dystrophy?

• A. Sign where the child slides through when lifted by the arms due to poor shoulder stabilization
• B. Sign of knee laxity when asked to squat
• C. Sign of hip instability when lifting
• D. Sign of rapid ankle dorsiflexion

Answer: (A)

In Duchenne muscular dystrophy, weakness of the shoulder girdle and the muscles that stabilize the scapula leads to poor proximal upper-limb control. The Meryon or Slip-through sign is when you lift a child by the arms and their body slips through your hands because the muscles around the shoulder girdle can’t maintain stable contact or support. This shows a failure of proximal upper-extremity strength and scapular stabilization that is typical of early to mid Duchenne progression.

The other described signs involve the lower extremities or ankle motion and don’t reflect this proximal upper-extremity weakness. Knee laxity on squatting or hip instability when lifting point to different joints, while rapid ankle dorsiflexion isn’t a characteristic upper-limb sign in Duchenne.