126 ARTHROLOGY, OR ANATOMY OF ARTICULATIONS 



tissue united to the periosteum of the posterior half of the 

 glenoid fossa; this is compressed or stretched according to 

 the position of the condyle. 



The stylomandibular ligament has nothing to do with this 

 articulation; it is a band of cervical fascia connected at one 

 end by aid of the styloglossus muscle to the styloid process, 

 and by the other to the angle and posterior border of the 

 lower jaw. It separates the parotid from the submaxillary 

 gland. 



Nerves of the joint are the auriculotemporal and masseteric 

 from the inferior maxillary. 



Arteries are temporal, the deep auricular, and tympanic 

 branches of the internal maxillary. 



Actions of the joint are protrusion and retraction, elevation 

 and depression, or a rotation when one side acts. The move- 

 ments in the superior and inferior compartments are of different 

 kinds; in the upper the fibrocartilage glides forward and back- 

 ward, and in the lower the condyle rotates against it on 

 a transverse axis. Elevation and depression take place on a 

 transverse axis through the centres of the rami some say 

 through the interarticular cartilages. If the depression be 

 considerable, the condyle also has a gliding motion, carrying 

 the cartilage with it. Rotary movement to one or other side 

 takes place on an axis through the opposite condyle. Depres- 

 sion is produced by the weight of the jaw, platysma, digastric, 

 mylohyoid, and geniohyoid muscles; elevation by the temporal, 

 masseter, and internal pterygoid; protrusion by the external 

 pterygoid, internal pterygoid, and superficial fibers of the 

 masseter; retraction by the deep fibers of the masseter and 

 posterior fibers of the temporal. It is a ginglymoarthrodial 

 joint. 



THE ARTICULATIONS OF THE VERTEBRAL COLUMN 

 WITH THE PELVIS 



The ligaments connecting the lumbar vertebra with the 

 sacrum arc the continuation of the ligaments which connect 

 the processes of the lumbar vertebra with each other. They 

 are the lumbosacral and iliolumbar ligaments. 



The lumbosacral ligament is attached above to the trans- 



