Final answer:
The triangular section that begins at the apex and ends at the front corners is referred to as the Frontal ridge, which is part of the frontal bone above the supraorbital margin.
Step-by-step explanation:
The triangular section in the question that begins at the apex and ends at the front corners is d) Frontal ridge. The frontal ridge refers to the thickened part of the frontal bone of the skull, which is located just above each supraorbital margin. This region forms the rounded brow ridges, located just behind the eyebrows, and plays a role as the roof of the orbit below and the floor of the anterior cranial cavity above. The frontal bone also contributes to the cranial structure by joining right and left parietal bones along the coronal suture and forming the anterior cranium.
It is formed by the frontal bone, which extends posteriorly to form the roof of the orbit and the floor of the anterior cranial cavity. The frontal bone also has rounded brow ridges located just behind the eyebrows.