274 



ARTICULATIONS. 



The External Lateral Ligament (Fig. 188) is a short, thin, and narrow fasci- 

 culus attached above to the outer surface of the zygoma and to the rough 

 tubercle on its lower border ; below, to the outer surface and posterior border 

 of the neck of the lower jaw. This ligament is broader above than below ; 

 its fibres are placed parallel with one another, and directed obliquely down- 

 wards and backwards. Externally, it is covered by the parotid gland, and by 

 the integument. Internally, it is in relation with the interarticular fibro- 

 cartilage and the synovial membranes. 



The Internal Lateral Ligament (Fig. 189) is a long, thin, and loose band, 

 which is attached above to the spinous process of the sphenoid bone, and be- 

 coming broader as it descends, is 



Fig. 189. Temporo-maxillary Articulation. inserted into the inner margin of 

 Internal View. t h e dental foramen. Its outer sur- 



face is in relation above with the 

 External Pterygoid muscle ; lower 

 down it is separated from the neck 

 of the condyle by the internal 

 maxillary artery; and still more 

 inferiorly the inferior dental ves- 

 sels and nerve separate it from the 

 ramus of the jaw. Internally it is 

 in relation with the Internal Ptery- 

 goid. 1 



The Stylo-maxillary Ligament is 

 a thin aponeurotic cord, which ex- 

 tends from near the apex of the 

 styloid process of the temporal 

 bone, to the angle and posterior 

 border of the ramus of the lower 

 jaw, between the Masseter and In- 

 ternal Pterygoid muscles. This 

 ligament separates the parotid from 

 the submaxillary gland, and has 

 attached to its inner side part of 

 the fibres of origin of the Stylo- 

 glossus muscle. Although usually classed among the ligaments of the jaw, it 

 can only be considered as an accessory in the articulation. 



Along with the stylo-maxillary ligament, although in no way connected with 

 the functions of the lower jaw, may be described the slylo-hyoid ligament. This 

 is a fibrous cord, which continues the styloid process down to the hyoid bone, 

 being attached to the tip of the former and the small cornu of the latter. It is 

 often more or less ossified. 



The Capsular Ligament consists of a thin and loose ligamentous capsule, 

 attached above to the circumference of the glenoid cavity and the articular 

 surface immediately in front : below, to the neck of the condyle of the lower 

 jaw. It consists of a few thin scattered fibres, and can hardly be considered as 

 a distinct ligament ; it is thickest at the back part of the articulation. 



The Interarticular Fibro-cartilage (Fig. 190) is a thin plate of an oval form, 

 placed horizontally between the condyle of the jaw and the glenoid cavity. 

 Its upper surface is concave from before backwards, and a little convex 

 transversely, to accommodate itself to the form of the glenoid cavity. Its 

 under surface, where it is in contact with the condyle, is concave. Its circum- 

 ference is connected externally to the external lateral ligament ; internally, to 

 the capsular ligament ; and in front to the tendon of the External Pterygoid 



1 Dr. Humphry describes the internal portion of the capsular ligament separately, as the 

 short internal lateral ligament ; and it certainly seems as deserving of a separate description as 

 the external lateral ligament is. 



