Although we have entered a modern society with many advanced and highly technical examination methods, physical and self examinations of the breast are still methods that should not be discarded because they are the most convenient, least invasive, most economical and most easily reapplied. It does not require any equipment, has a good sensitivity for lesions up to a certain size, and complements the device examination in at least two ways: by detecting to some extent lesions that are occasionally missed by the device examination and by detecting lesions between device examinations. The methods of physical examination and self-examination are in principle the same, except that visual examination during self-examination is performed with the aid of a mirror. It is important to make it a habit to perform a self-examination every menstrual cycle in order to have a sufficient understanding of the characteristics of your own breast, which facilitates the timely detection of new changes in the breast. If possible, it is best to schedule your mammogram between periods because this is the time when the breast is the smallest, minor abnormalities are easiest to detect, and the nature of the lesion is easiest to determine. The examination should cover all areas with breast tissue, including the axillae and supraclavicular fossa. It is important to perform a comparative bilateral breast examination. It is best to remove the upper garment and to have good lighting conditions during the breast examination. In order to clarify the timing and evolution of the breast abnormalities, the examination can be accompanied by the necessary questioning. First, a seated visual examination is performed. The size and contour of the breasts are first compared. In some women, bilateral breast development may not be identical, and this can be easily clarified by examination. If the difference in breast size is recent or if the difference has changed recently, then inflammation and malignant tumors should be considered. Localized abnormalities in the shape of the breast are actually more meaningful. For example, superficial or large tumors can cause localized augmentation, while malignant tumors, fat necrosis of the breast, and plasmacytoid mastitis can cause localized skin depressions, resulting in the “dimple sign. The “dimple sign” is usually a sign of involvement of the suspensory ligament of the breast, which can lose elasticity or even shorten, and pull the superficial fascia and skin, causing the local skin to sink deeper. Since the suspensory ligament has to cross the breast tissue, this sign may appear in both superficial and deep tumors. The dimple sign can appear when the tumor is small and no skin invasion has occurred. The dimple sign is no longer an early sign of breast cancer, but a clear sign of locally advanced cancer. Therefore, it is clinically important to identify the two types of skin dimples with or without skin invasion. In the dimple sign caused by the involvement of suspensory ligament alone, there is still fat and other subcutaneous tissues between the skin and the tumor, so there can be a certain degree of relative movement between the skin and the tumor. In contrast, when the tumor invades the skin, there must be adhesions between the skin and the tumor, and there will be no relative movement, but complete “welding” together. Chronic inflammation, fat necrosis, subcutaneous thrombophlebitis and post-surgical changes of the breast can also cause skin depression, among which the latter should be distinguished from malignant tumor recurrence. Methods such as having the patient lift the upper limb and pushing the breast upward under the lesion can be beneficial in detecting skin depression, but the latter operation can also induce pseudo-depression. Second, dilated veins and skin edema Dilated breast veins are also a noteworthy sign, which are often caused by inflammation and malignant tumors, especially sarcomas. However, benign giant fibroids can also cause this sign. Skin edema of the breast is another important sign that must be carefully observed, sometimes even with the help of a magnifying glass. It is important to mark the edema edges, measure the edema area and record the edema site in time. There are many causes of edema, skin invasion of tumor is the first cause that should be considered. It is also a sign of locally advanced cancer. In breast cancer, edema is often orange peel-like, because the skin becomes thicker when edema is present, and the skin at the follicle cannot swell with other parts of the skin, thus forming a small dotted depression, which resembles orange peel. Localized edema is most often found in the lower part of the breast and around the areola, and it is easier to detect edema in the upper extremities when the subject is raised. Some primary disease of the axillary lymph nodes and severe metastases of the tumor, as well as axillary lymph node dissection, can also lead to breast edema. Radiotherapy can also cause breast skin edema. Redness and edema of the breast skin are often due to inflammation and abscesses, but it is important to be aware of the possibility of inflammatory breast cancer. Skin changes in inflammatory breast cancer often involve all or a large portion of the breast, and there is usually no significant local tenderness or generalized fever. Large breasts may sometimes have mild edema in the area of the ptosis that disappears when lying down. This condition is not pathognomonic. III. Nipple and areola changes Tumors in the adjacent central region tend to draw the nipple toward the site where the tumor is located, or hold the nipple up. There are two major types of nipple invagination: congenital and acquired. The recent appearance of nipple invagination should be noted for the possibility of breast cancer, although ductal dilatation can also cause invagination, and interruption of breastfeeding can result in short-lived invagination. Changes in the elasticity of the externally drawn nipple compared to the bilateral one are likely to detect abnormalities before nipple invagination. Crusting, desquamation, erosion and eczema-like changes of the nipple and areola are the first signs of eczema-like carcinoma of the nipple areola (Paget’s disease), which can be limited at first but gradually extend to the entire nipple. When nipple overflow is detected, it is important to pay attention to the location and number of overflow duct openings and the nature of the overflow. The basic technique of palpation is to place the middle three fingers together, with the metacarpophalangeal joints slightly bent, and place the end finger belly (not the fingertips) flat on the breast for touching. The fingers are used to push the corresponding part of the breast skin in a circular motion, assuming that there is a small lump at some depth under the skin that you are trying to find. Each area should be touched with varying degrees of force from light to heavy to ensure that the different depths of tissue can be clearly palpated. Do not examine the breast with a palm pinch grip to avoid the illusion of a lump. 1. Stand in front of a mirror, cross your arms, lift your chest and tuck your abdomen, and compare the shape and size of both breasts, which under normal circumstances can also differ in size. The abnormalities mainly include: nipple overflow, skin wrinkling, and dimple sign. 2. Lift the left upper limb and touch the left breast slowly, steadily and carefully with the index, middle and ring fingers of the right hand, using a carpet inspection method, starting from the outside and slowly and spirally touching the breast for a week. Be careful not to miss the part of the breast near the armpit, clavicle and the lower part of the breast. 3.Gently squeeze the nipple to check for nipple discharge. 4.Lift the right upper limb and repeat steps 2 and 3 to examine the right breast with the left hand. 5.Check both breasts in the prone position. When lying flat, the upper limb to be tested is lifted over the head and placed behind the pillow, and a folded towel is placed under the shoulder to be tested; this position makes the breast lying flat easy to examine. Normal breast tissue, especially with breast hyperplasia, is not uniform in texture, and the subcutaneous fat can be in small lumps, so normal breasts are slightly nodular on palpation, with the outer upper quadrant, under the areola, and the glandular fold near the lowest point of the breast being the most concentrated areas of nodules. Clinically significant lumps often differ from the surrounding tissue in shape and texture.