What passes through the foramen caecum of the frontal bone?

The foramen caecum of the frontal bone usually communicates with the nasal cavity and may transmit small veins. On the internal base of the skull, the foramen caecum also connects the anterior cranial fossa with the nasal cavity, and its content is an emissary vein.

Into which nasal meatus does the aperture of the frontal sinus open?

The aperture of the frontal sinus allows the sinus to communicate with the nasal cavity. On the lateral wall of the nasal cavity, the middle nasal meatus communicates with the anterior and middle ethmoidal cells, as well as with the frontal and maxillary sinuses.

Which skull bones does the frontal bone articulate with?

The nasal margin of the frontal bone articulates with the nasal bones and the frontal processes of the maxillae.

Which specific vessels and nerves pass through the supraorbital notch?

The supraorbital notch or foramen transmits the frontal nerve, the supraorbital vessels, and vessels and nerves supplying the skin of the forehead, muscles, and periosteum.

What is found on the supraorbital margin of the frontal bone?

On the medial half of the margin lie the supraorbital notch or foramen and the frontal notch or foramen. These transmit the corresponding vessels and nerves.

Which structure on the internal surface of the squama serves for attachment of the falx cerebri?

The falx cerebri attaches to the frontal crest (Crista frontalis), which continues the sulcus for the superior sagittal sinus.

Where is the fossa for the lacrimal gland located?

It lies on the orbital surface (Facies orbitalis), on the lateral side, near the zygomatic process of the frontal bone.

Frontal Bone: Anatomy, Parts and Frontal Sinus

Frontal Bone

Os frontale

For medical students2 min readUpdated 2026-10-10

The frontal bone (Os frontale) is an unpaired pneumatic bone of the skull that forms the anterior part of the cranial vault and the superior wall of the orbits. It consists of a vertical squama, paired horizontal orbital parts, and a nasal part situated between them.

Bone typePneumatic bone (contains the frontal sinus)

PartsSquama, paired orbital part, and unpaired nasal part

Role in the skullForms the superior wall of the orbit

LandmarkGlabella above the root of the nose

Frontal Squama

The frontal squama (Squama frontalis) is the unpaired and largest part of the bone.

The external surface (Facies externa) blends laterally into the temporal surface (Facies temporalis), and its posterior border is the parietal margin (Margo parietalis). Inferiorly, the surface is bounded by the supraorbital margin (Margo supraorbitalis), which continues laterally into the zygomatic process (Processus zygomaticus).

The medial half of the supraorbital margin shows individual variation:

Here lies the supraorbital notch or foramen (Incisura / Foramen supraorbitale), through which the corresponding vessels and nerve pass.
Closer to the midline (toward the glabella), a frontal notch or foramen (Incisura / Foramen frontale) is often found.

Above the orbital margin, the superciliary arches (Arcus superciliares) project, with variable prominence, and above them lie the frontal eminences (Eminentiae frontales). Exactly on the midline, directly above the root of the nose, is a smooth area called the glabella (Glabella).

The internal surface (Facies interna) faces the brain. From its upper border, the sulcus for the superior sagittal sinus (Sulcus sinus sagittalis superioris) descends along the midline. Inferiorly it narrows and continues as the frontal crest (Crista frontalis), which serves as the attachment site for the falx cerebri. Lateral to the base of the crest lies the foramen caecum (Foramen caecum), which usually communicates with the nasal cavity and may transmit small veins.

Nasal and Orbital Parts

The nasal part (Pars nasalis) is the smallest structure of the frontal bone. It is unpaired, located below the squama, and wedged between the two orbital parts. Along the midline, a nasal spine (Spina nasalis) projects downward, acting as a support for the nasal septum. Externally, this part is bounded by the nasal margin (Margo nasalis), which articulates with the nasal bones and the frontal processes of the maxillae.

The orbital part (Pars orbitalis) is paired. It forms the superior wall of the orbit by means of its orbital surface (Facies orbitalis). On this surface are two important depressions:

On the lateral side, near the zygomatic process — the fossa for the lacrimal gland (Fossa glandulae lacrimalis).
On the medial side — the trochlear fovea (Fovea trochlearis), where the trochlea of the superior oblique muscle of the eye is anchored.

Posteriorly, the orbital parts end at the sphenoidal margin (Margo sphenoidalis). Between the right and left orbital parts remains a free space — the ethmoidal notch (Incisura ethmoidalis), intended for articulation with the cribriform plate.

Frontal Sinus

Since the frontal bone is pneumatic, the frontal sinus (Sinus frontalis) lies within the thickness of its squama, usually just above the supraorbital margin.

The sinus is divided into two halves by a septum (Septum sinuum frontalium). The shape of the sinuses and the position of the septum vary considerably between individuals. The cavity is not isolated: it communicates with the nasal cavity through a dedicated aperture (Apertura sinus frontalis).

Mnemonic

The frontal bone has "SON" — Squama, Orbital part, and Nasal part.

Frequently asked questions

What passes through the foramen caecum of the frontal bone?: The foramen caecum of the frontal bone usually communicates with the nasal cavity and may transmit small veins. On the internal base of the skull, the foramen caecum also connects the anterior cranial fossa with the nasal cavity, and its content is an emissary vein.
Into which nasal meatus does the aperture of the frontal sinus open?: The aperture of the frontal sinus allows the sinus to communicate with the nasal cavity. On the lateral wall of the nasal cavity, the middle nasal meatus communicates with the anterior and middle ethmoidal cells, as well as with the frontal and maxillary sinuses.
Which skull bones does the frontal bone articulate with?: The nasal margin of the frontal bone articulates with the nasal bones and the frontal processes of the maxillae.
Which specific vessels and nerves pass through the supraorbital notch?: The supraorbital notch or foramen transmits the frontal nerve, the supraorbital vessels, and vessels and nerves supplying the skin of the forehead, muscles, and periosteum.
What is found on the supraorbital margin of the frontal bone?: On the medial half of the margin lie the supraorbital notch or foramen and the frontal notch or foramen. These transmit the corresponding vessels and nerves.
Which structure on the internal surface of the squama serves for attachment of the falx cerebri?: The falx cerebri attaches to the frontal crest (Crista frontalis), which continues the sulcus for the superior sagittal sinus.
Where is the fossa for the lacrimal gland located?: It lies on the orbital surface (Facies orbitalis), on the lateral side, near the zygomatic process of the frontal bone.

Go deeper

Variations in the foramina and notches of the supraorbital margin
Relationship of the foramen caecum to the venous system of the nasal cavity
Individual anatomical variability of the frontal sinuses and their septum
Topography of the connections between the ethmoidal notch and the ethmoid bone