110 HANDBOOK OF ANATOMY 



individuals. On the inner surface of the bone is a large foramen 

 for the inferior dental nerve, and overhanging it a small spur 

 of bone, called the lingula. The ramus ends above in two 

 processes the coronoid anteriorly and the articular condyle 

 posteriorly. Between them is a notch the sigmoid notch. 



The mandible articulates with the temporal bone. 



The Hyoid bone is a small U-shaped bone lying between the 

 mandible and the larynx, and connected to the skull by liga- 

 ments from the styloid process of the temporal bone ; it is not 

 articulated with any bones. 



The bone cpnsists of a small body with two large processes,, 

 the great cornua projecting backwards and, where the great 

 cornua join the body, two small pointed processes, the lesser 

 cornua, projecting obliquely upwards. 



The hyoid bone has a large number of muscles attached to it,, 

 and owing to its loose connection with the skull gives great 

 mobility to this region. 



Joints of the Skull. 



All the joints of the head and face, with the exception of the 

 temporo-mandibular, are sutures. These are immovable joints 

 formed by dentated edges fitted together and firmly united by 

 means of cartilage. 



Temporo-Mandibular Joint between the condyle of the man- 

 dible and the articular hollow at the root of the zygomatic 

 process of the temporal bone. 



The joint is a very movable one, the condyle being almost 

 cylindrical in shape, with its long axis directed outwards and 

 forwards. The articular or glenoid fossa is saddle-shaped, 

 being concavo-convex from behind forwards. The joint is 

 divided into an upper and lower part by a meniscus of fibro- 

 cartilage, which compensates for the difference in shape of the 

 two surfaces. 



Owing to this construction the joint is particularly movable, 

 and the two joints need not always act simultaneously, but can 

 do so alternately, which gives a lateral movement to the jaw. 

 The movements possible are 



Transverse axis raising and depressing of mandible. 



