TEMPORO-MAXILLARY ARTICrLATIOX. 



145 



connection -with the joint, and by some anatomists is not recognised as 

 a liij'ament. 



The interarticular fibro-cartilage is a thin plate plaGcd between 

 the articular surfaces of the bones. It is of an oval form, broadest 

 transversely, thickest posteriorly, and thinnest at its centre, where it 

 is sometimes perforated. The inferior surface, which is in contact with 

 the condyle, is concave ; the superior is concavo-convex from before 

 backwards, conforming with the articular snrface of the temporal bone. 

 Its circumference is connected at the outside with the external lateral 

 ligament, and anteriorly with the external pterygoid muscle. 



Synovial Membranes. — The synovial membrane which lies between 



Fix. 1-32. 



Fig. 132. — Antero-Posterior 

 Section of the Tejiporo- 

 M AXILLARY Articulation 

 OF the right side. (A. T.) ^ 



1, is placed close to the 

 articular eminence, and points 

 to the superior synovial cavity 

 of the joint ; '2, is placed 

 close to the articular surface 

 of the head of the lower jaw, 

 and points to the inferior 

 synovial cavity of the joint ; 

 X , is placed on the thicker 

 Ijosterior portion of the inter- 

 articiilar tibro-cartilatre. 



the interarticular fibro- 

 cartilage and the glenoid 

 cavity is larger and looser 

 than that which is in- 

 terposed between the 



fibro-cartilage and the condyle of the jaw. When the fibro-cartilage 

 is perforated, the upper and lower synovial cavities necessarily com- 

 municate witli each other. 



The stylo-maxillary ligament is the name given to a strong 

 thickened band of fibres connected with the cervical fascia extending 

 from near the point of the styloid process to the posterior border of the 

 ramus of the jaw, where it is inserted between the masseter and 

 internal pterygoid muscles. It separates the parotid from the sub- 

 maxillary gland. 



It may be proper also to mention in this place the stylo-liyoid liga- 

 ment, a thin fibrous cord, which extends from the point of the styloid 

 ]n'ocess to the lesser cornu of the hyoid bone, and serves to suspend 

 that bone from the styloid process. A considerable portion of the 

 stylo-hyoid ligament is sometimes converted into bone in the human 

 subject, and in many animals it is naturally osseous, constituting the 

 ejniti/al hone. 



Movements. — The jaw is capable of movements of elevation and depression, 

 of some degi-ee of lateral displacement, and of protraction and retraction ; but it 

 is to be observed that when the jaw is depressed, as in opening the mouth, the 

 condyle advances from the glenoid cavity so as to be placed on the articular 

 eminence in front of it. The movements which take place in the superior and 



VOL. I. L 



