The frontal bone forms the forehead and has several parts including the vertical, orbital, and nasal parts. It has both external and internal surfaces. The external surface is smooth and convex while the internal surface is deeply concave to house the frontal lobe of the brain. Several features are present on both surfaces including the supraorbital margin, notch, foramen, tuberosity, and glabella. The frontal bone articulates with several other bones at the coronal and frontonasal sutures, ethmoid notch, and orbital plates.

1. Frontal bone

2. Frontal bone
• Forms forehead
• Parts: vertical part, orbital plate,nasal part
• Surfaces: external and internal,rt and left temporal surface
• Rt and lt orbital surface

3. External surface
• Smooth and convex

4. Frontal / metopic suture
• Present in 9% of individual
• At median plane
• Lower part
• Indicates line of fusion during
development

5. Supra orbital margin
• On each side
• Concave margins of orbital
opening
• Sharp and prominent on lateral
2/3
• Rounded on medial 1/3
• Presents Supra orbital foramen
or canal

6. Supra orbital foramen/ notch&Supra
trochlear foramen
• Present at meeting point of
medial1/3& lateral2/3 of Supra
orbital margin
• Transmitting Supra orbital nerves
and vessels
• Supra trochlear foramen present
occassionally medial to Supra
orbital notch / canal
• Transmitting Supra trochlear
nerves and vessels

7. Frontal tuberosity/eminence
• Round elevation
• On either sides
• About 3cm
• Above Supra orbital margin

8. Super cilliary arch
• Arched eminence
• On each side
• Above Supra orbital margin
• Separated from frontal
prominence by shallow
depression

9. Glabella
• Smooth
• Elevation
• In the median part
• Between super cilliary arches

10. Nasal part:
• Nasal notch: irregular notch,
articulate with nasal, frontal
process of maxilla,lacrimal bone
• Nasal spine:pointed projectin
downward at median plane
• Nasal groove: groove on either
side of nasal spine

11. Internal surface
• Deeply concave
• Lodges frontal lobe of brain with
its meninges

12. Sagittal sulcus
• Vertical groove
• At median plane
• Lodges superior sagittal sinus
• Margin receives attachment of
falx cerebri

13. Frontal crest
• Margins of sagittal sulcus unite
• To form a ridge/ crest
• Attachment: falx cerebri

14. Foramen caecum
• Frontal crest ends in a notch
• Convert into foramen
• In articulating with crista galli of
ethmoid bone
• When present transmitts vein
from nasal mucosa_ sup sagittal
sinus

15. Granular fovelae
• Irregular pits on each side of
sagittal sulcus
• Lodges arachnid granulations

16. Impression for cerebral sulci & gyri
• On each side

17. Furrow for middle meningeal vessels

18. Temporal surface
• Separated from frontal surface
by superior temporal line

19. Orbital parts
•
• Thin triangular plates
• Either side
• Forms roof of orbit

20. Lacrimal fossa
• Shallow depression
• Anterolateral part of orbital
plate
• Lodges lacrimal gland

21. Trochlear fossa/spine
• Below medial end of Supra
orbital margin
• Gives attachment to
fibrocartilaginous pulley of
superior oblique muscle

22. Ethmoid notch
• U shaped notch
• Median plane
• Separating medial margins of
orbital plates
• Articulats with cribriform plate
of ethmoid

23. Anterior and posterior ethmoidal canals
•
• Transverse groove at
marginof ethmoid notch
• Complete in articulation to
form ant and post
ethmoidal canals
• Transmitts anterior and
posterior ethmoidal nerves
and vessels

24. Posterior border of orbital plates
• Thin
• Serrated
• Articulate: anterior border of
lesser wing of sphenoid

25. Parietal border
• Serrated
• Articulate with: frontal border of
parietal bone and forms coronal
suture

26. Bregma
• Meeting point of two parietal
with frontal
• Meeting point of sagittal and
coronal sutures
• Site of anterior frontanellae

27. Nasion
• Meeting point of two nasal bone
with frontal bone
• Meeting pont of internasal
suture with frontonasal suture

28. Frontal air sinus
• Irregular cavities
• On either side of median plane