The part of the mammary gland zoning clinically common is to refer to the hands of the clock, the number is divided into 12 equal points, to the nipple as the center, was radial each different o’clock position represents a different breast area. Such as 12 o’clock for the nipple directly above, 9 o’clock for the outside of the mammary gland, that is, the left side of the left breast, the right side of the right breast. Therefore, 10 o’clock is the center of 9 and 12 o’clock, i.e., the left breast is the upper left and the right breast is the upper right area. There is another way to draw a cross with the nipple as the center, and the breast area is divided into 4 equal parts, inner upper quadrant, outer upper quadrant, inner lower quadrant, inner lower quadrant, etc. Therefore, 10 o’clock on the right breast is the middle of 9 o’clock and 12 o’clock. Therefore, the 10 o’clock direction of the right breast is the upper outer quadrant or the upper outer quadrant, which is a common site of breast cancer. If the site suggests abnormalities such as nodules or lumps, a biopsy should be performed for pathologic diagnosis.