What is shrinkage of a paralyzed muscle due to loss of neural connection called?

• A. Disuse atrophy
• B. Denervation atrophy
• C. Hypertrophy
• D. Myopathy

Answer: (B)

Denervation atrophy is the shrinkage of a muscle that results from losing its nerve supply. When the motor nerve to a muscle is damaged or cut, the muscle no longer receives the trophic signals and regular electrical activity it needs. This drop in neural input causes a decrease in muscle protein synthesis and an increase in protein breakdown, so the muscle fibers shorten and the muscle mass decreases. This is different from disuse atrophy, which happens when a muscle is not used but remains innervated; hypertrophy refers to muscle enlargement from increased workload, and myopathy is disease of the muscle tissue itself rather than a loss of nerve connection. Denervation atrophy specifically reflects the impact of losing neural input on muscle size.