Final answer:
The brow ridge consists of a thickened bone region just above the eyes, generally more pronounced in males and varying among individuals. In addition to its structural role, the brow ridge can significantly influence an individual's appearance, and make-up techniques can affect its perceived size and shape.
Step-by-step explanation:
The brow ridge refers to the area of bone that is located above the eyes on the frontal bone of the skull. These ridges are thicker and larger in some individuals, most often in males. The frontal bone itself is thickened above the supraorbital margin, forming what we commonly refer to as the brow ridges, which are just behind the eyebrows and play a critical role in various facial expressions and their intensity.
In regard to human evolution, a prominent example of a species with a pronounced brow ridge is Homo erectus, as presented in Figure 5.10. In contemporary humans, individuals with a more pronounced brow ridge may experience a masculine appearance since the feature is associated with higher levels of testosterone. Conversely, in makeup and cosmetic practices, there are several methods such as eyebrow shaders, pencils, gels, and powders to enhance or alter the appearance of the eyebrow and by extension the perceived prominence of the brow ridge.