Many patients and friends have the feeling that it is very difficult to go to a large public hospital to see a doctor because of the number of patients, often to see a doctor to spend a day, sometimes the wrong number, but also to re-queue for registration, waiting in line to be seen, not to mention the waste of money, but also delayed. Some seemingly simple symptoms, specific to the hospital, which department to see even the nurse guide is difficult to accurately determine, the patient and family members do not know how to consult. Leg pain is a common symptom, but at the same time, it is a symptom that can be manifested by many diseases. The same kind of irritation can be manifested as severe pain in some patients, while others may only feel vague discomfort. Some people have pain when lying still or at rest, others have pain after exercise, and it is important to go into detail about how to seek medical attention. The lower extremities of the human body we can roughly divide into the hip, thigh, calf, foot, and the part of the thigh connected to the abdomen is called the groin. The bones in front of the lower leg, commonly known as the welcome bone by the people, are called the tibia in medicine. The simplest leg pain is leg pain caused by trauma, with a recent clear experience of trauma, some people also have skin wounds, generally in this case to see orthopedics, certain general hospital subspecialties more detailed, to see the Department of Orthopedic Trauma. The sciatic nerve emanates from the lumbar spine and travels down the hip and outer thigh. When it is pressured or otherwise stimulated, the pain or discomfort caused by it is mainly distributed in the area from the hip, outer thigh to outer calf, where there are no important blood vessels, so symptoms in this area generally require orthopedic consultation. Herpes zoster is a viral infection that is commonly known as tangles when it occurs between the lower back. Occasionally, it can also occur in the lower extremities. It causes severe pain that travels along the distribution of nerves, and even touching the skin feels like a burning sharp pain, which is called pain hypersensitivity. Whereas there is no surface redness, swelling, or fever, and the doctor’s examination may not reveal anything specific, the diagnosis is confirmed only when herpes appears, and an experienced doctor may take this diagnosis into account before the blisters appear. This condition requires a visit to a dermatologist. Pain near joints, especially sports-related pain is usually seen in orthopedics, or osteoarthritis, but some redness and pain in the ankle joint, or redness and pain in the small joints of the toes, is checked for uric acid levels in the blood, and if elevated it may be gout, and is seen in internal medicine. Some may also be a manifestation of rheumatoid arthritis and need to see an immunologist. In some cases, the pain in the lower extremity is accompanied by a large red swelling, which can be discolored when pressed with a finger, and localized fever with obvious tenderness, which is often a manifestation of inflammation, clinically called reticulolymphangitis, also known as dermatitis, which is a surgical infection, and can be seen in general surgery or vascular surgery. Sometimes the redness and swelling are distributed in lines along the inner side of the lower limb, and subcutaneous cords can be palpated at the red line with obvious tenderness, which is a manifestation of superficial venous thrombophlebitis, and can be seen by vascular surgery. Some of the lower limb pain is related to lower limb activity, when walking a certain distance after the pain and discomfort, and eventually the patient is forced to stop to get better, such pain is called intermittent claudication. This type of pain can be seen in patients with arterial lesions, venous lesions, or lumbar spinal stenosis. Intermittent claudication caused by arterial stenosis or occlusion is generally caused by walking roughly the same distance each time the symptoms are induced, and can get better after a few moments of rest, and then can walk about the same distance again, and such patients are often accompanied by some manifestations of ischemia in the affected limb, such as pale skin, cold skin temperature, loss of dorsalis pedis artery pulsation, and muscle atrophy; intermittent claudication caused by venous causes does not necessarily walk the same distance each time it occurs. The main sensation is swelling and pain, accompanied by lower limb edema, heaviness, and blackness above the ankle, and some are accompanied by obvious varicose veins; the walking distance of claudication due to spinal stenosis varies, and the attack requires squatting or sitting down to relieve it. Arterial and venous claudication need to be seen by vascular surgery, and spinal stenosis by spine surgery or orthopedics. There are some lower extremity pains that are not related to movement and are evident when the patient is at bed rest, clinically known as resting pain. It is often associated with severe lower extremity ischemia. Due to poor blood supply to the tissues, patients often need to drape their lower extremities under the bed (so as to increase blood perfusion pressure less) or are unable to rest in bed and must sit upright. Pain medication for this ischemic pain is also ineffective. Some people also have necrosis of the lower limbs. These patients should definitely be seen by a vascular surgeon. In conclusion, although there are more manifestations of lower extremity pain and this article may not be comprehensive, the main departments involved are vascular surgery, orthopedics (joint/spine), dermatology, and partly internal medicine because of the relatively simple tissue structure of the lower extremity.