Lower extremity intermuscular vein thrombosis is not very serious. Lower extremity superficial muscular vein thrombosis is often not very serious, but there is some danger. In the case of simple intermuscular vein thrombosis of the lower limb, which is usually a thrombosis caused by a branch of the deep vein of the lower limb, the clinical manifestations tend to be pain, swelling, and a decrease in the local skin temperature, etc., but these symptoms are usually mild. When intermuscular vein thrombosis occurs in the lower limb, appropriate treatment should be carried out in time. The nature of thrombus can be clarified by D-dimer examination, whether it is old or fresh thrombus; then the degree of spread of thrombus can be clarified by ultrasound of the veins of the lower limb, and then the treatment can be carried out in time. Blood clots in the intermuscular veins of the lower limbs are easily dislodged, and the dislodged blood clots can easily flow with the blood to the pulmonary artery, thus leading to embolism of the pulmonary artery, which is a relatively serious disease with a high fatality rate. Intermuscular vein thrombosis of the lower extremities is not very serious, but if the thrombus is dislodged, it can easily lead to pulmonary embolism. Therefore, when intermuscular vein thrombosis occurs in the lower limbs, you should go to the hospital in time and get appropriate treatment under the doctor’s guidance.