Which conditions link brisk knee jerks and absent plantar response, amongst others symptoms such as..?

Nerve damage foot: Can be nerve damage in the leg/foot at the level of the knee, muscle weakness in the calf/leg, restriction/disease in ankle/foot joints preventing motion, or improperly performed test. Follow up with nerve conduction velocities and EMG studies with a neurologist. Other etiologies/causes are possible. If with severe pain, then immediate testing and evaluation for vascular compromise necessary.