Introduction and terminology

Throughout history a great many cultures have represented the forehead as the emblem of intelligence and high thought, presumably because behind it lie the frontal lobes of the brain, responsible for behaviour, learning and personality (Figure 11.1).

The forehead is the region of the face between the hairline and the eyebrows, formed by the smooth convexity of the frontal bone. The inferior aspect of the forehead merges seamlessly with the superior margin of each orbit. Just above each orbital margin is the variably prominent superciliary arch, alternatively termed the brow ridge or supraorbital ridge, which is usually more prominent in the adult male. These arches are united across the midline by another prominent ridge, the glabella. Beneath the superciliary arch on the frontal bone is the supraorbital rim/arch/margin, a curved and prominent margin that forms the upper boundary of the orbit and separates the vertical from the horizontal portion of the frontal bone (Figure 11.2).

The forehead is often an uneventful facial aesthetic unit; its inferior landmarks are commonly used as stable points from which to evaluate the relative position of mid and lower facial structures. However, patients with certain craniofacial syndromes, such as the craniosynostoses, may have considerable disproportion of the forehead region and cranium, which requires careful evaluation.

Anatomy

The frontal bone provides the skeletal framework for the upper facial third, occupying the upper third of the anterior view of the adult skull. The squamous part of the bone curves upwards and backwards from the upper margins of the orbits and nose. Medially its inferior border articulates with the frontal process of each maxilla, between which it articulates with the nasal bones. Laterally it projects down as a zygomatic process, articulating with the frontal process of the zygomatic bone, together forming the lateral margin of the orbit (Figure 11.2).

The supraorbital part of the frontal bone contains the two frontal paranasal air sinuses. These are irregularly shaped cavities which extend, to a variable extent, backwards into the roof of the orbit and upwards into the frontal region. They are separated from each other by a septum, which often deviates considerably from the median plane; as a result the two sinuses are frequently of unequal size. The frontal air sinuses vary greatly in size and shape from one individual to another. They are the only sinuses not present at birth; they appear during the second year of life, enlarge considerably during adolescence due to enlargement of the frontal bone and continue to grow, albeit more slowly and essentially by resorption of the surrounding cancellous bone, throughout adult life.

The prominence of the supraorbital ridge is variable, and often more pronounced in males than females.

Clinical evaluation

Clinical evaluation of the upper facial third is primarily concerned with the relative size, shape and degree of protrusion of the forehead. The forehead, which is the area from trichion (hairline) to and including the glabellar region, is considered as a single facial aesthetic unit, comprised of two subunits (Figure 11.3):¹

• Superior forehead subunit.
  
• Supraorbital ridge‐lateral orbital rim subunit, which includes the glabellar region.