Frontal bossing is when the forehead becomes bigger than normal which may also make the brow ridge stick out more. It happens when the frontal bone becomes bigger because of a medical condition. This often happens when other facial bones of the skull become bigger too, as well as the jaw bone and the bones in the hands and feet. Frontal bossing is usually seen in a few rare medical syndromes such as acromegaly - a chronic medical disorder in which the anterior pituitary gland makes to much growth hormone (GH).