THE TEMPOROMAXILLARY ARTICULATION 125 



in front with the external pterygoid muscle; it is composed 

 of concentric fibers; its circumference is thick, and its centre 

 may be perforated. 



There are two synovial membranes : the upper is the larger 

 and prolonged in front, while the lower is smaller and pro- 

 longed behind. 



The external lateral ligament (ligamentum accessorium 

 laterale) passes from the outer surface of the zygoma and 

 tubercle; their lower borders down and back to the posterior 

 surface of the neck of the lower jaw. Externally it is in rela- 

 tion with the temporal fascia, and internally with the joint 

 capsule. 



FIG. 22 



Vertical section of the temporomandibular articulation. 



The internal lateral ligament (ligamentum accessorium 

 mediale) has two parts: One passes from the inner margin 

 of the glenoid fossa to the neck of the condyle behind the 

 insertion of the external pterygoid muscle; this is in immediate 

 relation to the capsule, and is known as the short internal 

 lateral ligament. The other passes from the spine of the sphenoid 

 to the lingula and inner margin of the dental foramen (spheno- 

 mandibular). Between these two ligaments are the internal 

 maxillary artery and veins, and lower down the auriculotemporal 

 and inferior dental nerves; internal to the long band is the 

 internal pterygoid muscle. Between the short internal lateral 

 and the synovial membrane is a pad of soft elastic connective 



