In which condition are inhibitory nerves cut and spinal reflexes cause sustained contraction?

• A. Atony
• B. Spasticity
• C. Myositis
• D. Rupture

Answer: (B)

Spasticity is the result of reduced inhibitory input from the brain to the spinal cord, so the spinal reflexes become hyperactive. When inhibitory pathways are diminished, motor neurons are more easily excited by reflexes like the stretch reflex, leading to a continuous or sustained contraction and increased muscle tone. This is typically described as a velocity-dependent increase in tone with intermittent involuntary contractions.

Atony would mean low or flaccid muscle tone, not sustained contraction. Myositis involves inflammation of the muscle, often with weakness and pain rather than preserved or increased tone. Rupture is a torn tissue, not a state of neural inhibition or reflex-driven contraction.