60 SURGICAL ANATOMY OF 



between it and the ramus of the jaw are the inferior 

 dental vessels and nerve; and on its inner side is the in- 

 ternal pterygoid muscle. The stylo-maxillary ligament, 

 really a slip of the deep cervical fascia, is attached to 

 the styloid process of the temporal bone and to the in- 

 ferior angle of the lower jaw, it separates the parotid 

 from the submaxillary gland, and gives origin to some 

 fibres of the stylo-glossus muscle. 



Owing to the numerous movements which the mus- 

 cles of mastication are capable of causing, and to the 

 comparative laxity of the ligaments of the articulation, 

 the lower jawbone is liable to partial or complete dislo- 

 cation. The condyles glide forward, carrying the inter- 

 articular nbro-cartilages with them, upon the eminently 

 articulares, in such conditions as yawning or laughing, 

 or masticating large morsels ; the combined action of the 

 masseter and internal pterygoid muscles drags them 

 under the zygomatic arches, whilst the temporal muscles 

 drag the displaced bone upwards. The obstacle to re- 

 duction appears to be, that in most cases the coronoid 

 process is, as it were, locked in front of the malar tuber- 

 cle. Partial luxation of one condyle is of common oc- 

 currence, and occasionally a portion of that process of 

 the parotid which wraps round the neck of the jaw is 

 included between the opposing surfaces, causing severe 

 pain and inconvenience. The principle upon which re- 

 duction is effected is by introducing some solid body 

 between the molar teeth so as to form a fulcrum, whilst 

 the power is applied at the symphysis, at the same time 

 that the angles are depressed. 



