The motor level is the most caudal key muscle with at least 3/5 strength, provided the muscles above are functionally intact. In this case, knee extension (L3) is 3+/5, which meets the ≥3 requirement, and hip flexion (L2) is 4/5, indicating preserved function above. The rule does not require the muscle above to be 5/5, just that it is not absent. Since ankle musculature (L4–S1) is absent, L3 is the lowest functioning level and therefore the suspected neurological level. If this were truly an L2 injury, we would expect knee extension to be less than 3/5 or absent. For sensory, he has not sensation behind the knee (S2) and at the ankle (L3-S1), and nothing in the stem say L3 dermatome is absent, so you cannot assume L3 sensory loss. So, based on this, L3 is the likely neurological level.
