Although we have entered the modern world with many advanced and highly technical screening methods, physical examination of the breast and self-examination remain methods that should not be discarded because they are the most convenient, the least invasive, the most economical and the most easily reapplied. It does not require any equipment, has a decent sensitivity for lesions up to a certain size, and complements the equipment examination in at least two ways: by detecting, to some extent, lesions occasionally missed by the equipment examination and by detecting lesions in the intervals of the equipment examination. The methods of physical and self-examination are in principle the same, except that the visual diagnosis in self-examination is made with the aid of a mirror. It is important to get into the habit of carrying out self-examinations every menstrual cycle in order to have a sufficient knowledge of the characteristics of one’s own mammary glands, which facilitates the timely detection of new changes in the breasts. If possible, it is best to schedule a mammogram between menstrual periods, as this is the time when the mammary glands are at their smallest size, when minor abnormalities are easiest to detect, and when the nature of the lesions is easiest to determine. The scope of the examination includes all areas with breast tissue distribution, but also the axilla and supraclavicular fossa. Care should be taken to perform a bilateral comparison of the breasts. It is advisable for the patient to be able to remove his/her shirt during the breast examination and to have good lighting conditions. In order to clarify the timing and evolution of breast abnormalities, the physical examination can be accompanied by the necessary inquiries. (i) Changes in appearance and the dimple sign Firstly, a sitting visualization is performed. The size and contour of the breasts are compared. In some women, the development of both breasts may not be identical, but this can be easily clarified by questioning. If the difference in size between the two breasts is recent or if the difference has changed recently, then inflammation and benign or malignant tumors should be considered. Abnormalities in the localized shape of the breast are actually more significant. For example, superficial or large tumors can cause localized elevation, and malignant tumors, breast fat necrosis, and plasma cell mastitis can cause localized skin depressions, resulting in the “dimple sign”. The “dimple sign” is usually a manifestation of the involvement of the suspensory ligament of the breast, which will lose its elasticity or even shorten, and pull the superficial fascia and the skin, causing the local skin to sink deeper. Since the suspensory ligament crosses the breast tissue, this sign may appear in superficial and deep tumors. The dimple sign can appear when the tumor is very small and no skin invasion has occurred. When the tumor has already invaded the skin, 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 and without skin invasion. In dimple sign caused by suspensory ligament involvement alone, there are 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. When the tumor invades the skin, there must be adhesion and fixation between the skin and the tumor, and there will be no relative movement, but completely “welded” together. Skin depression is not only caused by breast cancer, but also caused by chronic inflammation of the breast, fat necrosis, subcutaneous thrombophlebitis of the breast, and post-surgical changes, the latter of which should be distinguished from the recurrence of malignant tumors. Methods such as allowing the patient to lift the upper limbs and pushing the breast upward under the lesion can be beneficial in detecting skin dimpling, but the latter operation can also elicit false dimpling. (ii) Dilatation of the veins and skin edema Dilatation of the veins of the breast is also a noteworthy sign, and it is often caused by inflammation and malignant tumors, especially sarcomas. However, benign giant fibrous tumors can also cause this sign. Edema of the breast skin is another important sign that must be carefully observed, sometimes even with the aid of a magnifying glass. The edges of the edema should be promptly labeled, the area of the edema measured, and the location of the edema recorded. There are many causes of edema, and skin invasion by the tumor is the cause that should be considered first. It is also a sign of locally advanced cancer. The edema of breast cancer is often orange peel-like, this is due to the thickening of the skin during edema, and the skin at the hair follicle can not follow the swelling of other parts of the skin, thus forming a point-like small depression, which resembles the orange peel, and this kind of edema is also known as the “orange peel sign”. Localized edema is most often seen in the lower part of the breast and around the areola, and is more easily detected when the subject lifts the upper extremities. Some primary diseases of the axillary lymph nodes and severe metastases of the tumor, as well as axillary lymph node dissection, can also lead to breast skin edema. Radiotherapy can also cause breast skin edema. Redness and edema of the breast skin is often due to inflammation and abscesses, but attention must be paid to the possibility of inflammatory breast cancer. Skin changes in inflammatory breast cancer often involve all or a large portion of the breast and are usually not associated with significant local tenderness or generalized warmth. Large breasts sometimes have mild edema in the sagging area, which disappears when lying down. This is not a pathological condition. (iii) Nipple and areola changes Tumors adjacent to the central region tend to draw the nipple toward the site of the tumor or hold it up. There are two main types of nipple inversion: congenital and acquired. Recent nipple inversion should be noted for the possibility of breast cancer, although ductal dilatation can also lead to inversion, and interruption of breastfeeding can result in short-term inversion. External pulling of the nipple to compare bilateral changes in elasticity is likely to detect an abnormality before nipple inversion. Crusting, flaking, erosion, and eczema-like changes of the nipple and areola are the first signs of eczema-like carcinoma of the nipple and areola (Paget’s disease), which can be limited at first but gradually extends to the entire nipple. When nipple discharge is detected, the location and number of overflow duct openings should be noted, as well as the character of the discharge. (d) Palpation The basic technique is to place the middle three fingers together, with the metacarpophalangeal joints slightly curved, and place the end fingers (not the tips) flat on the breast for palpation. The palpation is done by pushing the corresponding area of breast skin with the fingers in a range of circular pressing motions, assuming that a small lump is already present at a certain depth under the skin and that you are trying to locate it. Each area should be touched with varying degrees of force from light to heavy to ensure that different depths of tissue can be touched clearly. Do not examine the breast by pinching and gripping it with your palm to avoid the illusion of a lump. 1. Stand in front of a mirror, cross your arms, lift up your chest and tighten your abdomen, and compare the shape and size of the breasts on both sides. Under normal circumstances, there can be differences in the size of the breasts on both sides. Abnormalities mainly include: nipple overflow, skin wrinkling, dimple sign. 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, adopting the carpet-type examination method, starting from the outer side and slowly and spirally touching the breast for one week. Be careful not to miss the part of the breast near the armpit, collarbone and the lower part of the breast. 3.Gently squeeze the nipple to check for nipple overflow. Raise the right upper limb and repeat the steps in (2) and (3) to examine the right breast with the left hand. 5.Check both breasts in lying position. When lying down, the upper limbs to be examined are lifted above the head and put behind the pillow, and a folded towel is put under the shoulder to be examined, which makes the breasts lying down easy to be examined. Normal breast tissue, especially with breast hyperplasia breast gland texture is not uniform, and subcutaneous fat can also be a small lump-like, so the normal breast palpation is also slightly nodular, of which the outer upper quadrant, under the areola, the lowest point of the breast near the gland folds back is the most concentrated parts of the nodule. Clinically significant lumps often differ from the surrounding tissue in shape and texture.