I. Skin color examination method Skin color is an indicator to observe the function of peripheral vascular circulation. The capillaries in the skin of the extremities are rich and easy to observe the color change, especially the filling of capillaries in the skin of the fingers (toes), hands (feet) and nail bed is the easiest to observe. Observation of skin color changes should be examined in a room with a suitable temperature as much as possible, the room temperature should be controlled at 20℃~27℃ and natural light should be used as much as possible. (A) finger pressure test The examiner compresses the finger (toe) belly or nail bed with the finger to observe the capillary filling. Local pale when compressed, should quickly return to pink after release, the normal recovery time is 1 to 2 seconds. If the local arterial blood circulation is impaired, the filling is slow or locally pale or cyanotic after the pressure is released. Acupressure recovery time of more than 3 seconds is considered as abnormal arterial blood supply, and the longer the pale to red time, the more serious the limb ischemia. When observing the color of the nail bed in the acupressure test, attention should be paid to the patient’s slightly flexed fingers. When the fingers are hyperextended, the color of the nail bed is slightly pale, which can easily cause false positives and mislead the limb to have blood supply disorders. The acupressure test can also distinguish whether the limb tissue has been necrotic, and the acupressure test is performed in the cyanotic area of the skin. If there is continuous pallor under heavy pressure, it indicates that the local area has been severely hypoxic and the tissue has been inactivated. (B) Limb elevation and droop test Using the method of limb elevation or droop to cause postural changes in local limb blood pressure, and then to observe the changes in the skin. The method is to make the patient lie flat, the limb is naturally flat and straight, observe the color of the skin of the sole and toes (or palm fingers). If one limb or one toe (finger) or several toes (fingers) appears uniformly pale or florid cyanosis locally, it indicates the presence of limb ischemia. Limb elevation test: make both lower extremities 70° from the examination table and observe after 60 seconds, the normal skin should remain light red and slightly white. Ischemic limbs may be obviously pale or waxy white. The pallor of the ischemic limb after elevation is proportional to the severity of arterial obstruction, and the extent of pallor varies with the site of obstruction and is generally slightly below the plane of the obstructed artery. To perform the upper extremity elevation test, the patient stands with the hands raised above the head for a few seconds, and then is observed. The change in skin color that occurs from the elevated limb can be recovered within 10 seconds in normal individuals. In limb ischemia, it can be delayed to 45-60 seconds or longer, and the skin color is unevenly patchy. Limb prolapse test: When the limb is in prolapse, normal people have no special change in skin color or only a mild flushing. Those with impaired blood circulation may show severe cyanosis, which is due to hypoxia and vascular congestion at the extremity. In varicose veins and venous valve insufficiency, the prolapse test is meaningless. Second, the skin temperature measurement method individual differences in skin temperature, so individuals can not be compared with the absolute value of skin temperature, the skin temperature of different parts of the human body is also different, generally the trunk temperature than the extremities, the temperature of the toes is lower; hand temperature is higher than the foot temperature, thumb (toe) temperature is higher than the little finger (toe) temperature. Skin temperature is also affected by room temperature, emotions, exercise, hunger and satiety, smoking and other factors. The skin temperature of the symmetrical part of the same body is approximately the same, and the temperature difference should not exceed 2℃. If the difference in skin temperature of the symmetrical part is more than 2℃ or there is a significant decrease, it indicates that the local limb has ischemia. When measuring the skin temperature of the limb, it should be measured in a room with a constant room temperature (20℃~27℃), with a quiet rest for 15~30 minutes, so that the skin temperature of the limb can be stabilized before measurement. Take symmetrical parts of the limb in different planes and measure at fixed points. A decrease in skin temperature suggests limb ischemia, while an increase in skin temperature is commonly associated with acute deep vein thrombosis and arteriovenous fistula. Peripheral arterial pulsation is an important step in the examination of peripheral vascular disease. When arterial disease is considered, the pulsations of major arteries throughout the body should be routinely examined. When arterial stenosis, obstruction, or atherosclerosis of the arterial wall occurs, the pulsation of the local or distal artery disappears or is weakened. Arterial pulsations can be enhanced in high temperature environments, elevated body temperature, and congenital arteriovenous fistulas. When examining arterial pulsations, it should be noted that: ① The major arteries of the body must be examined systematically. (2) Bilateral symmetrical site control examination. (3) Depending on the depth of the vessel, different pressure should be applied to the artery. If the arterial pulsation is weak or disappears, the patient should be careful not to mistake the examiner’s own finger pulsation for the patient’s arterial pulsation, but to check with the patient’s arterial pulsation on the opposite side or the patient’s heart rhythm. ⑤ Important vessels, such as the common carotid artery, should not be pressurized too heavily and examined for too long, so as not to cause cerebral ischemia. (6) While palpating the artery, it is necessary to understand the elasticity and hardness of the artery, the presence of twist, nodule and tremor, etc. (7) When examining the pulsation of an aneurysm, it is important to be gentle to avoid rupture of the aneurysm or dislodgement of the intra-aneurysm thrombus. There is no unified standard for grading the intensity of arterial pulsation in China, and the United States usually classifies the pulsation from disappearance to normal into five levels. Considering that certain diseases can lead to pulsation enhancement, we classify the arterial pulsation into six grades as follows: pulsation disappears (-), vaguely palpable (+), significantly attenuated (++), mildly attenuated (++++), normal (++++), and significantly enhanced (+++++). IV. Examination of vascular murmur Arterial stenosis caused by external pressure, arteritis, atherosclerosis, etc., and blood shunting caused by arteriovenous fistula can be heard as murmurs in the arterial body projection area. Arterial murmurs can be heard distally with blood flow. A murmur in the femoral artery suggests possible stenosis at the bifurcation of the common iliac artery. A systolic murmur in the supraclavicular fossa often indicates stenosis of the innominate artery or the artery at the opening of the subclavian artery, and a murmur in the bifurcation of the common carotid artery often indicates stenosis of the artery in that area. A murmur under the costal margin or in the posterior spinal rib angle, in conjunction with hypertension, suggests possible renal artery stenosis. A periaqueductal murmur often suggests a lesion in the lower abdominal aorta or in the bifurcation. When auscultating murmurs, the stethoscope should not be pressurized too heavily to avoid artificial stenosis and murmurs. V. Measurement of arterial blood pressure In arterial stenosis or obstruction, the blood pressure of the artery distal to the lesion is reduced or not measured. Measure the blood pressure in symmetrical parts of the limbs, the normal pressure difference should not exceed 15 mm Hg, and the normal lower limb blood pressure should be 15-25 mm Hg higher than the upper limb. If the blood pressure of one lower extremity is significantly lower than that of the upper extremity or the contralateral extremity, this indicates limb ischemia. Arterial pressure measurement of the extremities, applying a common sphygmomanometer and stethoscope, is only a preliminary measurement. If Doppler ultrasound flowmeters are available, the segmental systolic pressure of each limb can be accurately measured and the ankle/brachial blood pressure ratio can be used to estimate the arterial obstruction. The normal ankle/brachial ratio should be greater than 1.0. Measurement of limb length and circumference Abnormal lesions of arteries or veins, such as congenital arteriovenous fistula, Klipple-Trenaunay syndrome and other diseases, can often cause limb thickening and growth; venous obstructive diseases, such as acute and chronic deep vein thrombosis, lymphatic reflux disorders, etc., can cause limb swelling and thickening. The length and thickness of the limb are often measured during diagnosis and treatment to observe the extent of the lesion, the development of the disease and to judge the efficacy of treatment. The limb circumference measurement of the lower limb is more commonly used. The circumference of the lower limb should be measured at a distance of 15 cm below the patella and 20 cm above the patella, which is the limb circumference of the lower limb. The difference between the limb circumference of the normal person’s bilateral limbs should be less than 1 cm. Seven, gastrocnemius compression test (Neuhof) patient lying supine with knees bent and heels flat on the bed, the examiner presses the deep tissue of gastrocnemius with fingers or squeezes, if there is tenderness that is positive, mostly seen in acute gastrocnemius venous plexus thrombosis. The saphenous valve function test (Trendelenburg test), the traffic branch valve function test (Pratt test) and the deep vein patency test (Perthes test) can be used to understand the saphenous and traffic branch valve function and deep vein patency respectively, as a screening test for primary saphenous valve insufficiency, which has been gradually replaced by the Doppler test. Doppler examination has gradually replaced it.