The outside of the calf has a palm-sized place feel hot, not red and not swollen considerations with strenuous exercise, mental overstress and other physiological factors, but also considerations with the plant nerve disorders, peripheral neuropathy, lumbar intervertebral disc herniation, and so on. 1. Physiological factors: part of the population can be due to strenuous exercise, mental overstress, life stress, etc., and the outer calf has a palm-sized place feel hot, not red and not swollen phenomenon. 2. Vegetative nerve disorder: mainly related to psychosocial factors, genetic factors, biological factors and so on. Patients will have postural hypotension, chest tightness, numbness of the limbs, insomnia and forgetfulness, peripheral skin fever and other multi-system symptoms, which can be manifested in the outer calf with a palm-sized place feeling hot, not red and not swollen. 3. Peripheral neuropathy: the etiology is complex and may be related to nutrient metabolism, vasculitis, trauma and so on. Patients will have numbness or burning pain in the limbs, uncoordinated limb movements, muscle weakness, sensory loss and other symptoms, which can also be manifested as a feeling of warmth in the palm-sized area on the lateral side of the calf, without redness or swelling. 4. Lumbar intervertebral disc herniation: disc degeneration, chronic strain injury is the cause of lumbar intervertebral disc herniation, the typical symptoms of patients with lumbago, lower limb radiating pain, limb fatigue, sensory anomalies, and so on, can also be manifested as a palm-sized area on the outside of the lower leg feels hot, not red and not swollen. It is recommended that those who feel warmth in the palm-sized area of the outer calf, without redness or swelling, should consult a doctor in time for examination, so as to clarify the cause of the disease and then follow the doctor’s instructions for treatment.