OSTEOLOGY. 33 



BONES OF THE FACE 



are nine pairs and two single bones. We sliall first examine 

 the pairs. 



OS NASI is a fiat bone, forming tbe major part of the 

 roof of the nasal chamber; presents two surfaces, two 

 margins, a base, and an apex. The lase of this bone has a 

 squamous laminated surface for union with os frontis. 

 The inner margin is straight, and lies in apposition with the 

 corresponding part of its fellow. The outer margin meets 

 it at an extremely acute angle, and as the anterior part of 

 the outer margin is free, the two points coming together 

 produce a remarkable prominence, to which the nasal car- 

 tilages are attached, and which is termed the nasal peak. 

 From the external surface of the bone, near the outer margin 

 of the nasal peak, dilator naris superior arises ; behind this 

 the margin is in apposition with the upper extremity of 

 the superior process of the anterior maxillary bone. It 

 then presents thin horizontal plates fitting into os niaxil- 

 lare superius, and at the outer angle of the base is a line of 

 union with os lachrymale. The superior surface is convex ; 

 inclined obliquely outwards over it passes nasalis longus 

 labii superioris. The inner surface, correspondingly con- 

 cave, is partly occupied by the expanded upper portion of 

 septum nasi, but inclined to its outer side it presents a 

 ridge to which is attached OS turbinatum superius. The 

 turbinated bones are extremely thin and friable in the 

 dried subject, but when fresh they are coated on both sides 

 by mucous membrane, which renders them elastic. Each 

 of them consists of two portions, one anteriorly placed, 

 belonging to the nasal chamber, the other to the sinuses of 

 the head. These bones are supplied with nutriment by 

 their investing mucous membrane ; they therefore have no 

 periosteum. They will be noticed more particularly in our 

 description of the nasal chambers and the sinuses of the 

 head. 



Os turbinatum inferius is attached to the nasal surface 

 of the facial plate of the superior maxillary bone. 



Os maxillare anterius is situated at the anterior part of 

 the upper jaw, lodges the superior incisors, and forms the 

 outer and inferior boundary of the anterior opening into 

 the nasal fossae of the skeleton ; it consists of a body and 



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