Thigh root to knee pain can be seen in rheumatoid arthritis, neuropathy, quadriceps injury and other diseases. 1. Rheumatoid arthritis: the typical manifestation is wandering polyarthritis, often symmetrically involving the knee, ankle, shoulder, hip and other large joints; localized redness, swelling, heat, pain and other inflammatory manifestations. At this time, the symptoms of thigh root to knee pain may appear. 2. Neuropathy: Bone neuropathy is often seen in the lumbar intervertebral disc herniation caused by nerve compression, clinically manifested as radiating pain, limb numbness or coldness in the lower limbs. When the pain radiates to the leg, it can cause pain symptoms from the thigh root to the knee. 3. Quadriceps injury: the thigh root to the knee is the general location of the quadriceps muscle of the human body, when the quadriceps muscle is damaged, manifested as pain, accompanied by limited knee joint activity, weakness in lifting the leg and other symptoms. Thigh root to knee pain can also be seen in other causes, it is recommended that patients seek medical treatment in time, under the diagnosis and guidance of professional doctors for standardized treatment.