Breast dimple sign is generally identified from local skin depression, shape change and touch. 1. Localized skin depression: Normal breast shape is smooth and rounded arc, when breast cancer invades Cooper’s ligament, it will make the breast lose elasticity, and the skin pulls to the deep side to form the dimple sign. When breast examination is done, because Cooper’s ligament loses its elasticity, the skin connected with it is relatively depressed, and it appears to be different from the normal structure of the breast. 2. Shape change: due to the invasion of Cooper’s ligament by breast cancer, the shape of local skin of breast is changed, and patients often have dimple sign, and the enlargement of the lump leads to localized elevation of breast, obvious adhesion with surrounding skin, and asymmetric appearance of breast. 3. Touch: As breast cancer invades Cooper’s ligament, resulting in shortening of the ligament and dimple sign, it can be identified by touching, lying flat on the bed, touching the breast with the palm of the finger, checking the left breast with the right hand, and checking clockwise from the upper quadrant of the outer breast, and checking for indentation if a lump is touched. Meanwhile, the appearance of dimple sign is usually accompanied by a lump in the breast, orange peel sign, and enlarged lymph nodes. The identification of the dimple sign of breast cancer should be carried out under the guidance of a specialized doctor.