In males the hairline is often higher than in females and usually has receded corners above the temples that give it an "M" shape. The hairline can be moved forward and given a more rounded shape, either with a procedure called a "scalp advance" wherein the scalp is lifted and repositioned, or with hair transplantation.
Males tend to have a horizontal ridge of bone running across the forehead just above eyebrow level called the brow ridge (or "brow bossing"), which includes the "supraorbital rims" (the lower edge, on which the eyebrows sit). Males also tend to have indented temples and a flatter forehead than females.
The brow ridge is usually solid bone and can simply be ground down. The section of bossing between the eyebrows (the glabella) sits over a hollow area called the frontal sinus. The frontal sinus is hollow, and thus it can be more difficult to remove bossing there. If the bone over the frontal sinus is thick enough the bossing can be removed by simply grinding down the bone. However, in some people the wall of bone is so thin that it is not possible to grind the bossing away completely without breaking through the wall into the frontal sinus.
FFS surgeons have taken two main approaches to resolving this problem. The most conservative approach is to grind down the wall of bone as far as possible without breaking through, and then build up the area around any remaining bossing with hydroxyapatite bone cement which can smooth out any visible step between remaining bossing and the rest of the forehead. In these cases, some additional reduction in the bossing can sometimes be achieved by thinning the soft tissues that sit over it. Alternatively, FFS surgeons can perform a procedure called a forehead reconstruction or cranioplasty where the glabella bone is taken apart, thinned and re-shaped, and reassembled in the new feminine position with small titanium wires or titanium orthopedic plate and screws. The data on which approach is better is limited and does not provide guidance. The risks of cranioplasty include the skull not healing properly, movement of the bone fragments, and the formation of cysts; these can usually be corrected by another procedure
Men tend to have lower eyebrows relative to the position of their brow ridges when compared to women. Men's eyebrows tend to be below their brow ridges while women's eyebrows tend to be above their brow ridges. Accordingly, FFS to raise the eyebrows results in a face with a “womanlier” appearance.
In some literature the eye shape has been shown to be the key differentiating feature between males and females. Female eye sockets tend to be smaller, located higher on the face, to have more sharply angled outer edges, and to be closer together at their inner edges (the intercanthal distance). Some FFS alter the orbit shape; data on outcomes is limited.