osteology

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