Skeletal System:- Neurocranium - Frontal bone

Anatomy of the the frontal bone, an unpaired bowl-shaped bone located in the forehead region, which contributes in forming the cranium.

1. Frontal
Bone
Skeletal System
Neurocranium
Dr. Aves Khan
Oral & Dental
Surgeon

2. Introduction of
Frontal Bone
Thefrontalbone(latin:osfrontale)isanunpairedbowl-shapedbone
locatedintheforeheadregion,whichcontributesinformingthe
cranium.
Thefrontalboneliessuperiortothenasalbonesandanteriortothe
parietalbones.

3. Parts of
Frontal Bone
The Frontal bone has 4 parts –
1.squamous part,
2.orbital part (2),
3.nasal part.

4. Squamous part of
the frontal bone
Itisthelargestpartofthefrontalbonewhichformstheareaof
theforehead.
Thesquamouspartofthefrontalbonehousesthefrontal
sinuses,whichareseparatedbyaseptumandarelocatedabove
theorbits.

5. Orbital or
horizontal partof
the Frontal bone
Itformstheroofoftheorbitandethmoidalsinuses.
Theorbitalpartconsistsoftwoorbitalplatesseparatedbya
gap-theethmoidalnotch.

6. Nasal partof
theFrontal bone
Itislocatedanteriorlybetweenthetwoorbitalpartsof
thefrontalboneformingpartoftheroofofthenasalcavity.

7. Surfaces and
landmarks of
frontal bone
Thefrontal bonehas an external and an internal surface. Several
landmarks and structures can be found on each surface.
The external surface of thefrontal bonefeatures:
frontal eminence (2),
superciliaryarch (2),
glabella,
supraorbital margin (2), featuring
frontal notch (or foramen),
supraorbital notch (or foramen),
zygomatic process (2),
temporal line,
temporal surface.

8. The externalsurface
of thefrontal bone
Thefrontaleminenceisaroundelevationonthefrontal
bonelocatedabovethesupraorbitalmarginoneachsideofthe
frontalsuture.
Thesuperciliaryarchisanelevationonthefrontalboneabove
theuppermarginoftheorbit.Bothsuperciliaryarchesarejoined
togetherbytheglabella.
Theglabellaisasmoothelevationonthefrontalbone,a
landmarkbetweenthetwosuperciliaryarches.
Thesupraorbitalmarginistheupperorbitalmarginofthefrontal
bone.

9. The externalsurface
of thefrontal bone
Thefrontalnotch(sometimespresentingasfrontalforamen)is
anopeningoneachofthesupraorbitalmarginsofthefrontal
bonemedialtothesupraorbitalnotch(orforamen).
Thefrontalnotchorforamenservesasapassageforthe
supratrochleararteryandthemedialbranchofthesupraorbital
nerve.
Thesupraorbitalnotch(sometimespresentingassupraorbital
foramen)isanopeningpresentedasanotchoraholelocatedon
eachofthesupraorbitalmarginsofthefrontalbone.
Thesupraorbitalnotchorforamenisthepassageforthe
supraorbitalarteryandthelateralbranchofthesupraorbital
nerve.
Itisalsoapressurepointfortheophthalmicbranchofthe
trigeminalnerve.

10. The externalsurface
of thefrontal bone
Azygomaticprocessisapartofabonewhicharticulateswiththe
zygomaticbone.
Thezygomaticprocessofthefrontalboneisanextensionof
thefrontalbonelateraltotheorbit,anditistheprocessfor
articulationwiththezygomaticbone.
Thetemporallineofthefrontalboneisthecontinuationofthe
lineformedbytheunionofthesuperiorandinferiortemporal
linesoftheparietalbone.
Atemporalsurfaceofaboneisapartofabone,which
contributestotheformationofthetemporalfossa.
Thetemporalsurfaceofthefrontalboneistheexternal,lateral
surfaceofthefrontalbone,lateralfromthetemporallineof
thefrontalbone,formingtheanterosuperiorpartofthetemporal
fossa.

11. The internalsurface
of thefrontal bone
Theinternalsurfaceofthefrontalbonefeatures:
frontalcrest,
grooveforsuperiorsagittalsinus.
Thefrontalcrestisthemedianridgeontheinternalsurfaceof
thefrontalboneforattachmentofthefalxcerebri.
Thegrooveforthesuperiorsagittalsinusisashallowdepression
onthefrontal,parietal,andoccipitalbonesformingachannelfor
thesagittalsuperiorsinus;itsmarginscometogetherasitpasses
downwardandbecomecontinuouswiththefrontalcrest.

12. Anatomical
views of the
Ethmoid bone

13. Dr. Aves Khan
Oral & Dental
Surgeon