Dear , This is Dr. S.Tomar from Healthcaremagic.com s medical team and I will be your medical advisor for this question. Thank you for sharing your concern with us and showing trust on us. I would like to inform you that such indentation or slight dip is not uncommon and is mainly due to the imbalance of strength in those muscles which connects the rib to the sternum . Sometimes such conditions are seen due to mineral deficiency , Rickets , lung problems or recurrent chest infections as well . If you don t have any lung issue in past , any bone related abnormalities then such dip is of not much clinical importance and you should not be worried about . I would suggest you to start exercising like swimming which gives strength to chest muscles . I would also recommend you to consult your PCP also and get it examined . I wish you good health. This is my initial response and feel free to contact if you need any further clarification . Thank you for your question and feel free to contact us further for any query or follow up. sincerely, DR.S.TOMAR