INFERIOR TURBINATED BONE. 51 



maxillary fossa ; the internal lateral forms part of the lateral boun- 

 dary of the nares ; and the superior surface articulates with the 

 under part of the body of the sphenoid bone. 



The pterygoid process or tuberosity of the palate bone is the thick 

 and rough process which stands backwards from the angle of union 

 of the horizontal with the perpendicular portion of the bone. It is 

 received into the angular fissure, which exists between the two 

 plates of the pterygoid process at their inferior extremity, and pre- 

 sents three surfaces : one coacave and smooth, which forms part of 

 the pterygoid fossa ; and one at each side to articulate with the 

 pterygoid plates. The anterior face of this process articulates with 

 the superior maxillary bone. 



Developement. By a single centre. 



Articulations. With six bones; two of the cranium, the sphenoid 

 and ethmoid ; and four of the face, the superior maxillary, inferior 

 turbinated bone, vomer, and with the palate bone of the opposite 

 side. 



Attachment of Muscles. To four ; the tensor palati, azygos uvula, 

 internal, and external pterygoid. 



INFERIOR TURBINATED BONES. The inferior turbinated or spongy 

 bone is a thin layer of loose and spongy bone, slightly curled upon 

 itself, and projecting inwards from the inner wall of the nares. It 

 is developed from a single centre, and gives attachment to no 

 muscles. 



Articulations. With four bones; the ethmoid, superior maxillary, 

 lachrymal, and palate. 



VOMER. The vomer is a thin and quadrilateral plate, forming a 

 part of the septum of the nares. Superiorly, it is broad and expanded, 

 and forms a sheath for the rostrum of the sphenoid ; inferiorly, it is 

 thin, and received into a groove, formed by the articulation between 

 the palate processes of the superior maxillary and palate bone of 

 opposite sides. The posterior border is free, and divides the poste- 

 rior nares ; the anterior is rough, and often slit into two layers, to 

 receive the sharp edge of the perpendicular lamella of the ethmoid 

 bone, and of the cartilage of the septum. 



The vomer frequently presents a convexity to one or the other 

 side; it is developed by a single centre, and has no muscles attached 

 to it. 



Articulations. With six bones; the sphenoid, ethmoid, two supe- 

 rior maxillary, and two palate bones, and with the cartilage of the 

 septum. 



INFERIOR MAXILLARY BONE. The lower jaw is the arch of bone 

 which contains the inferior teeth ; it is divisible into a horizontal 

 portion or body, and a perpendicular portion, the ramus, at each 

 side. 



Upon the external surface of the body of the bone, at the middle 

 line, and extending from between the two first incisor teeth to the 

 chin, is a slight ridge, called the symphysis. Immediately external to 

 this ridge is a depression which gives origin to the depressor labii 



