Which reflex is tested at the L5 spinal level?

The hamstrings reflex is tested at the L5 spinal level because it involves the hamstring muscles, which are innervated by the sciatic nerve originating from the lumbar and sacral levels of the spinal cord, specifically L4 to S3. The reflex can be elicited by striking the tendons of the hamstring muscles, primarily the semitendinosus and semimembranosus, which results in flexion of the knee.

The other reflexes mentioned in the options are assessed at different spinal levels. The biceps reflex primarily relates to the C5 and C6 spinal levels, the triceps reflex corresponds to the C6 and C7 levels, and the patellar reflex involves the L3 and L4 levels. Therefore, the identification of the hamstrings reflex as being linked to the L5 spinal level accurately reflects its anatomical and neurological basis.