Start in the sitting position. Any nipple inversion, skin depression, and structural shape abnormalities are clues to cancer deep in the breast. These signs can occur if the patient claps her hands over her head to contract her pectoral muscles. When the woman is in the sitting position, it is easier to examine the supraclavicular, infraclavicular, and axillary lymph nodes, and finally to perform palpation while sitting, using joined fingers to touch the area under the nipple. In the supine position, a pillow is placed under the ipsilateral breast and the ipsilateral hand is raised above the head so that the breast is evenly spread on the chest wall, making it easy for the fingers to reach the deeper mammary glands, and the palm of the index, middle and ring fingers are used for palpation rather than the fingertips. Palpation should be performed in a circular fashion, turning laterally from the nipple outward, and it is especially important to examine the breast that extends into the armpit. The breast examination should first observe the development of the breast, whether both breasts are symmetrical, whether the size is similar, whether both nipples are at the same level, whether there is retraction of the nipple depression; whether there is erosion of the nipple and areola, what is the color of the breast skin, whether there is edema and orange peel-like changes, whether there is redness and swelling and other inflammatory manifestations, whether there is anger in the superficial veins of the breast area, etc. The best time for examination: For women with normal menstruation, the 9th to 11th day after menstruation is the best time for breast examination, when estrogen has the least effect on the breast and the breast is in a relatively quiescent state, making it easy to detect lesions. Lumps that appear during breastfeeding should be further examined after weaning if they are clinically suspected to be tumors. The breast gland is located on the surface of the body and is the easiest to examine by itself, and the self-detection of early breast tumors is substantially increased. If you find any abnormalities, you should go to the hospital in time.