4. The bridge of the nose

5. Superiorly each bone articulates with the frontal bone

6. laterally with frontal process of the maxilla

7. The cartilage of the external nose is attached to its inferior border

8. In the midline the two bones project backwards and formed part of the septum of the nose.

9. On the inner surface of each bone there is a longitudinal groove in which run the anterior ethmoidal vessels and nerve.

10. They pass on to the external surface of the nose between the bone and cartilage as the external nasal vessels and nerve.

12. median bone, which forms the postero-inferior part of the nasal septum

13. Posteriorly its upper margin is flattened to form two alae, which articulate with the inferior surface of the body of the sphenoid bone.

14. Its smooth posterior margin forms the free edge of the septum.

15. Inferiorly it articulates with the bones of the hard palate

16. antero-superiorly with the perpendicular plate of the ethmoid bone and the septal cartilage

18. a thin plate of bone on the lower part of the lateral wall of the nasal cavity

19. It projects medially and then downwards enclosing the inferior meatus.

20. Its upper lateral edge is attached, in front, to a ridge on the maxilla and behind to a ridge on the palatine bone.

21. The middle part of the bone has three processes: 1st process passing upwards, which close in the lower part of the nasolacrimal duct

22. 2nd process, which articulates with the ethmoid bone.

23. 3rd process, between these two, downwards and articulates with the maxilla.

24. All these processes reduce the size of the opening of the maxillary sinus.