THE TEMPORO-MAXILLARY JOINT 109 



conforms to the articular surface of the post-glenoid process and the 

 glenoid cavity. The cartilage extends right across the joint, and to 

 it the capsular ligament is firmly adherent on either side. This 

 ligament is attached around the borders of the articular surfaces of 

 the bones forming the joint. 



Running from the roughened aspect of the post-glenoid process 

 to be attached inferiorly to the back of the condyle just below the 

 margin of its articular surface, is the posterior ligament, which is 

 composed of yellow elastic fibres. 



There is only one other ligament in connection with this joint 

 in the horse, and this is placed on the external lateral aspect of the 

 joint. It is a slender band of white fibrous tissue, which runs from 

 the outer aspect of the condyle, where it is attached below the 

 articular surface, forwards and upwards, to be attached superiorly to 

 the inferior border of the zygomatic process of the squamous 

 temporal bone. 



This joint possesses two separate synovial membranes, one of which 

 is placed between the condyle and the cartilage, and the other between 

 the cartilage and the articular surface of the squamous temporal bone. 



When the mouth is closed the cartilage and condyle are in 

 position as described above. When the animal opens its mouth the 

 two condyles are rotated on an imaginary horizontal axis passing 

 through their centres. Whilst the condyle is being thus moved in 

 the depression on the inferior aspect of the cartilage, the latter glides 

 forwards along the articular eminence, so that when the mouth is 

 fully opened the condyle and the articular eminence lie in the same 

 vertical plane. During the closure of the mouth the cartilage glides 

 backwards, and the condyle of the inferior maxilla is once more 

 directly beneath the glenoid cavity. Lateral movement of the joint, 

 such as is necessary when the molars triturate the food material, is 

 permitted owing to the slight convexity of the condyle in the 

 transverse direction. 



