NORMA FRONTALIS OF THE SKULL. 145 
fissure there is a smaller circular opening, the optic foramen (foramen opticum), for 
the transmission of the optic nerve and ophthalmic artery. 
Fia, 114.—Norma FRonvALIs, 
1. Mental protuberance. 13. Optic foramen. 
2. Body of lower jaw. 14, Orbital foramina. 
3. Ramus of lower jaw. 15. Temporal ridge. 
4. Anterior nasal spine. 16. Supraorbital notch. 
5. Canine fossa. 17. Glabella, 
6. Infraorbital canal. 18. Frontal eminence. 
7. Malar canal. 19. Superciliary ridge. 
8. Orbital surface of superior 20, Parietal bone. 
maxilla, 21. Fronto-nasal suture. 
9. Temporal fossa. 22. Pterion. 
10. Os planum of ethmoid, 23. Great wing of sphenoid. 
11. Sphenoidal fissure. 24, Orbital surface of great wing 
12. Lachrymal bone and groove. of sphenoid. 
25, 
26. 
Palle 
28. 
29. 
30. 
ol. 
32. 
3b4, 
35. 
Squamous temporal. 
Left nasal bone. 
Malar bone. 
Spheno-maxillary fissure. 
Zygomatic arch. 
Anterior nasal aperture, displaying 
nasal septum and inferior and 
middle turbinated bones. 
Mastoid process. 
Incisor fossa. 
Angle of jaw. 
Mental foramen. 
Symphysis. 
The roof of the orbit, which is very thin and brittle towards its centre, is formed 
in front by the orbital plate of the frontal bone (pars orbitalis) and behind by a 
small triangular piece of the lesser wing of the sphenoid, which surrounds the 
1 
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