OS HYOIDES. 



189 



meatuses, formed between three horizontal plates of bone that spring from it; 

 they are termed the superior, middle, and inferior meatuses of the nose. The 

 superior meatus, the smallest of the three, is situated at the upper and back part 

 of each nasal fossa, occupying the posterior third of the outer wall. It is 



Fig. 134. Inner Wall of Nasal Fossae, or Septum of Nose. 



Crcxt of Jfasal lont. 

 Nasal Sjttin* oj frontal fi. 



Space for Triangula 

 CartiLatje of Septum 



situated between the superior and middle turbinated bones, and has opening 

 into it two foramina, the spheno-palatine at the back of its outer wall, the pos- 

 terior ethmoidal cells 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 fossse, im- 

 mediately 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 infundibulum, by which the middle meatus communi- 

 cates with the anterior ethmoidal cells, and through these with the frontal 

 sinuses. At the centre of the outer wall is the orifice of the antrurn, which 

 varies somewhat as to its exact position in different skulls. The inferior meatus, 

 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, because it supports the tongue, and gives attach- 

 ment to its numerous muscles. It is a bony arch, shaped like a horseshoe, and 

 consisting of five segments, a body, two greater cornua, and two lesser cornua. 



The Body forms the central part of the bone, and is of a quadrilateral form: 

 its anterior surface (Fig. 135) convex, directed forwards and upwards, is divided 



