<prompt> Root value of knee-jerk -L1L2L3L4L5S1S1 S2  <response>: Ans. is b i.e., L3L4ReflexRoot valueBiceps reflex biceps jerkC5 C6Supinator reflex Supinator jerkC5 C6Triceps reflex Triceps jerkC7 C8Knee jerkL3 L4Ankle jerkS1 S2 