Frontal bone
The frontal bone is one of the thickest bones of the skull. At birth, it is usually paired – right and left – but before the first year of life, the suture separating them (sutura frontalis s. metopica ) usually ossifies1 . The occurrence of persistent metopic suture in adult age varies in different countries from nearly 0% to 15%, and it should not be confused with the frontal bone fracture2 .
1 Vu H, et al. The timing of physiologic closure of the metopic suture: a review of 159 patients using reconstructed 3D CT scans of the craniofacial region. Journal of Craniofacial Surgery, 2001, 12(6):527-532.
2 Zdilla M, et al. Metopism: a study of the persistent metopic suture. Journal of Craniofacial Surgery, 2018, 29(1):204-208.
Frontal bone in situ & ex situ .
Please note the variable pattern of sutures along the perimeter of that bone, from the serrated (between the frontal and parietal bone ) to squamous (between the frontal and the lesser wing of sphenoid ).
Anterior aspect of frontal bone.
Note the specific shape of the nasal part designed to simultaneously articulate with ethmoid , sphenoid , nasal and lacrimal bones.
The list of terms:
Squama frontalis – Squama of frontal bone
Tuber frontale – Frontal tuber
Sutura metopica – Frontal, or metopic suture
Processus zygomaticus – Zygomatic process
Linea temporalis – Temporal line of frontal bone
Arcus superciliaris – Superciliary arch
Margo supraorbitalis – Supraorbital border
Incisura / foramen supraorbitale – Supraorbital notch or foramen
Incisura / foramen frontale – Frontal notch or foramen
Pars nasalis – Nasal part of frontal bone
Spina nasalis – Nasal spine
Margo nasalis – Nasal border
Dorsal aspect of the frontal bone.
The list of terms:
Sulcus sinus sagittalis superioris – Groove for superior sagittal sinus
Crista frontalis – Frontal crest
Foramen caecum – Foramen cecum
Impressiones digitatae – Digitate impressions
Juga cerebralia – Cerebral ridges of cranium
Sulci arteriae meningeae mediae – Groove for middle meningeal artery
The bottom aspect of the frontal bone demonstrating an opening of the frontal sinus (apertura sinus frontalis ).
The list of terms:
Pars nasalis – Nasal part
Spina nasalis – Nasal spine
Margo nasalis – Nasal border
Apertura sinus frontalis – Opening of frontal sinus
Incisura frontalis – Frontal notch
Foramen supraorbitale – Supraorbital foramen
Incisura supraorbitalis – Supraorbital notch
Incisura ethmoidalis – Ethmoid notch
Pars orbitalis – Orbital part
Fossa glandulae lacrimalis – Fossa for lacrimal gland
Foramen ethmoidale anterius – Anterior ethmoid foramen
The postero-lateral aspect of the frontal bone.
The list of terms:
Squama frontalis – Squama of frontal bone
Margo parietalis – Parietal border
Linea temporalis – Temporal line of frontal bone
Facies temporalis – Temporal surface
Processus zygomaticus ossis frontalis – Zygomatic process of frontal bone
Pars orbitalis – Orbital part
Incisura ethmoidalis – Ethmoid notch
Frontal bone ex situ & in situ . 360° rotation.
First published: May/2019
Last update: 09/Nov/2020