OS Hi'OIDES. 



Ill 



at the front part of the upper wall. The opening of the sphenoidal sinuses is 

 usually at the upper and back part of the nasal fossa3, immediately behind the 

 superior turbinated bone. The middle meatus is situated between the middle and 

 inferior turbinated bones, and occupies the posterior two-thirds of the outer wall 

 of the nasal fossa. It presents two apertures. In front is the orifice of the infun- 

 dibulum, by which the middle meatus communicates with the anterior ethmoidal 

 cells, and through these with the frontal sinuses. At the centre of the outer wall 



Fig. C7. Inner Wall of Nasal Fossae, or Septum of Nose. 



Crest of If and Ion*. 



Nu.3al Sjnnt of frontal f{. 



Space for Triangular 

 of Septum 



Crat of Palate Bi> tl ,,, 

 Crest of 8up.Mcunll.f>nt 



is the orifice of the antrum, which varies somewhat as to its exact position in 

 different skulls. The inferior meat-its, the largest of the three, is the space between 

 the inferior turbinated bone and the floor of the nasal fossa. It extends along the 

 entire length of the outer wall of the nose, is broader in front than behind, and 

 presents anteriorly the lower orifice of the lachrymal canal. 



Os HYOIDES. 



The Hyoid bone is named from its resemblance to the Greek Upsilon ; it is also 

 called the lingual bone, from supporting the tongue, and giving attachment to its 

 numerous muscles. It is a bony arch, shaped 

 like a horseshoe, and consisting of five seg- 

 ments, a central portion or body, two greater 

 cornua, and two lesser cornua. 



The Body forms the central part of the 

 bone, is of a quadrilateral form, its anterior 

 surface (fig. 68), convex, directed forwards 

 and upwards, is divided into two parts by 

 a vertical ridge, which descends along the 

 median line, and is crossed at right angles by 

 a horizontal ridge, so that this surface is 

 divided into four muscular depressions. At 

 the point of meeting of these two lines is a 



Fig. 68. Hyoid Bone. Anterior Surface. 



