The frontal bone, specifically its squamous (flat) part,
forms the skeleton of the forehead, articulating inferiorly
with the nasal and zygomatic bones. In some adults a frontal
suture persists; this remnant is called a metopic suture. It is
in the middle of the glabella, the smooth, slightly depressed
area between the superciliary arches. The frontal suture
divides the frontal bones of the fetal cranium.
The intersection of the frontal and nasal bones is the
nasion (Latin nasus, nose), which in most people is related to
a distinctly depressed area (bridge of nose). The nasion is one of many craniometric points that are
used radiographically in medicine (or on dry crania in physical anthropology) to make cranial measurements, compare
and describe the topography of the cranium, and document
abnormal variations. The frontal bone
also articulates with the lacrimal, ethmoid, and sphenoids; a
horizontal portion of bone (orbital part) forms both the roof
of the orbit and part of the floor of the anterior part of the
cranial cavity.
The supra-orbital margin of the frontal bone, the angular boundary between the squamous and orbital parts, has a
supra-orbital foramen (notch) in some crania for passage
of the supra-orbital nerve and vessels. Just superior to the
supra-orbital margin is a ridge, the superciliary arch, that
extends laterally on each side from the glabella. The prominence of this ridge, deep to the eyebrows, is generally greater
in males.