The tendons on the back of the foot protrude, the following common causes: 1, dorsal foot sprain: in the stairs or sports, can occur dorsal foot tendon sprain, the patient will appear local swelling, tendon protrusion and accompanied by local pressure symptoms, skin temperature will also be significantly increased, through cold compress treatment and affected limb braking, pain and tendon protrusion will completely disappear. 2, dorsal foot varicose veins: lower limb varicose veins or ambient temperature is too high. All of them can lead to dilatation of veins on the back of the foot, which is manifested by the protrusion of local tendons, and there is no obvious pain symptom when pressed, and the symptoms can be gradually relieved by elevating the affected limb. Therefore, if the tendons on the back of the foot protrude, it is not necessarily a serious disease, and early diagnosis and early treatment may lead to complete relief of clinical symptoms, so there is no need to worry excessively.