Deep vein thrombosis is one of the common clinical diseases. Generally speaking, the common clinical manifestations are as follows: 1. Skin pigmentation of the affected limb accompanied by itching, which is mainly due to the obstruction of venous return of the lower limbs, local congestion and lack of sufficient nutrients, resulting in skin ischemia and hypoxia of the lower limbs and itching and pigmentation. 2. Acute cerebral embolism manifestations such as sudden limitation of limb movement, aphasia, coma, etc. This is due to the detachment of deep vein thrombosis in the lower extremities and blockage of intracranial veins, resulting in the above symptoms. 3. Sudden dyspnea, respiratory failure, venous thrombus falling off and blocking large blood vessels in the lungs, resulting in acute pulmonary embolism.