Question: What are differences between withdrawal and crossed-extensor reflexes? The withdrawal reflex activates muscles on one side of the body, whereas crossed-extensor reflex activates muscles on both sides of the body. The withdrawal reflex only activates muscles, whereas the crossed-extensor reflex activates and inhibits muscles. The withdrawal reflexes only activate trunk muscles, whereas the crossed-extensor reflex can activate any of the appendages. The withdrawal reflex is a monosynaptic reflex, whereas the crossed-extensor reflex is a polysynaptic reflex.