The forehead is the region of the head formed by the large, shell-shaped frontal bone, which is one of the eight bones that make up the cranium. This single bone provides structural support for the face, including the eye orbits and nasal passages, while also serving a protective role for the brain. The physical appearance and size of this area are not static but change over the course of a lifespan, reflecting the dynamic nature of the human skeletal structure.
Cranial Growth During Infancy and Childhood
The initial growth of the forehead is characterized by a rapid, expansive process designed to accommodate the quickly developing brain. At birth, the skull is not a single fused unit but consists of several separate bones joined by flexible seams called sutures and membranous gaps known as fontanelles, or soft spots. The frontal bone itself begins as two halves separated by the metopic suture, which typically fuses completely within the first year of life.
The fontanelles allow for the necessary increase in cranial volume. The anterior fontanelle, located at the top-front of the head, is particularly relevant to the forehead area and remains open longer than others. It generally closes between seven and nineteen months of age. The majority of overall skull size growth is completed by age seven, a period dominated by volumetric expansion.
Shaping the Forehead in Adolescence
Adolescence marks a transition from general volumetric expansion to the final structural shaping and definition of the forehead. This phase is significant because hormonal shifts lead to the emergence of sexual dimorphism, the physical differences between males and females. The influx of sex hormones, particularly testosterone, influences the final form of the frontal bone through bone deposition and remodeling.
In males, this hormonal activity often results in the greater development of the supraorbital ridge, commonly known as the brow ridge, and a slight forward projection called frontal bossing. Consequently, the adult male forehead often presents as more oblique or sloped compared to that of a female. Conversely, the female forehead tends to retain a flatter, more vertical, and rounded appearance. The facial skeleton undergoes a final growth spurt during puberty that solidifies the forehead’s size and shape.
Changes in Adulthood and Aging
After skeletal maturity, which typically occurs in the late teens or early twenties, the primary growth of the frontal bone ceases. The cranial sutures solidify, meaning the bone can no longer expand in the way it did during childhood and adolescence. While major growth stops, the bone remains a living tissue that undergoes continuous, subtle remodeling through a balanced process of bone resorption and deposition throughout life.
The perception of a “growing forehead” in older adults is often attributable to changes in soft tissue rather than bone. Recession of the hairline, which is prevalent in many adults, exposes more of the scalp and frontal bone, creating the illusion of a larger or higher forehead. The loss of skin elasticity and the downward migration of soft tissues on the face also affect the appearance.
While some bone loss (resorption) does occur in the facial skeleton with age, the frontal bone remains remarkably stable. The most noticeable age-related changes are primarily due to the repositioning of the hairline and the aging of the skin and underlying fat pads.