The ossicles are the only human body parts that do not grow after birth. These three small bones are located in the middle ear and are about 3mm in size since birth. They remain the same size throughout a person's lifetime. Another body part that does not grow is the eyeball.
While it's a common misconception that the nose and ears never stop growing, the cartilage that makes up these parts does stop growing. However, cartilage is made of collagen and other fibers that break down with age, causing the nose and ears to appear larger.
The cornea of the eye is also sometimes cited as a part of the body that doesn't grow. However, this is incorrect. The cornea is the transparent outer layer of the eye and does increase in size throughout life, albeit at a much slower rate than other body parts.
