The knee-jerk reflex can not be elicited may be improper operation method, mental stress, nerve injury and other reasons.
1. Improper operation method: the knee-jerk reflex is when the knee is half-flexed and the calf is hanging down, knocking the quadriceps tendon under the patella, causing the quadriceps muscle to contract, so that the calf will make a knee-extension reaction. If the operation method is not correct, the knee-jerk reflex cannot be elicited.
2. Stress: If the person being examined for knee jerk reflex is in a state of stress, the knee jerk reflex may be weakened or even disappear, and the knee jerk reflex cannot be elicited.
3. Nerve damage: When the body suffers from diseases such as peripheral neuritis and radiculitis, which involve the L2-L4 nerves, the reflex arc is damaged and the afferent and efferent nerves are damaged, so the knee jerk reflex cannot be elicited.
There are many reasons why the knee-jerk reflex cannot be elicited, and it is necessary to go to the hospital for examination and judgment.