There is a ball-shaped hard mass in the middle depression of the two chests, which may be a normal physiological structure, namely the saber process. The saber process is located directly below the sternum, just a little below the middle depression of the two chests, and a hard, round-like object can be felt by pressing and touching with the hand. It is also considered to be a lump occurring in the skin or under the skin, and the symptoms are different and need to be treated accordingly after differential diagnosis. Common causes and treatments 1, mammary gland hyperplasia: mammary gland hyperplasia may occur in the middle recess of the two breasts. If the spherical hard mass is accompanied by pain, more rest is needed, and if the pain is obvious, you should go to the hospital for active treatment so as not to delay the disease; 2, sebaceous cyst: benign mass formed by the accumulation of sebum, which manifests as a spherical hard mass when it grows larger, can be removed as a whole through a small incision, but attention should be paid to complete removal, otherwise it is prone to recurrence; 3, boils: benign mass formed by the accumulation of sebum, which manifests as a spherical hard mass when it grows larger. Otherwise, it is easy to recur; 3. Boil: It is a purulent inflammation occurring from bacterial infection of hair follicles, accompanied by redness, swelling, heat and pain, and if there is pus accumulation, there will be fluctuation, i.e. fluctuating sensation. Boils can be treated with local physiotherapy, topical application of drugs such as Ruyi Jinhuang San or fish lithin ointment, and oral antibiotics in the early stage. If an abscess is formed, an incision and drainage is required. 4. Fibroma: a tumor derived from connective tissue, generally benign, occurs in the middle recess of the two chests and produces a ball-shaped hard lump with occasional slight pain, which needs only regular observation when it is small and does not require treatment. When the hard mass is larger or affects the beauty, it can be removed surgically; 5. Lipoma: it is a common benign tumor, which can occur under the skin in all parts of the body, and it is also a ball-shaped hard mass in the middle depression of the two chests, which generally needs no treatment. If there is a spherical hard mass in the middle depression of the two chests and the discomfort is obvious, to avoid delaying the treatment, it is necessary to go to the hospital for examination in time to understand the nature of the mass and the size of the mass, to clarify the specific cause of the disease, and to be judged by the doctor whether surgery is needed.