ARTICULATION OF THE LOWER JAW. 49 



fibres, passing obliquely backward from the tubercle of the 

 zygoma to the outer side of the neck of the lower jaw. 



The internal lateral ligament is a membranous expansion 

 from the spinous process of the sphenoid bone to the mar- 

 gin of the dental foramen ; the internal maxillary artery 

 and dental nerve pass between this ligament and the jaw. 



The stylo-maxillary ligament extends from the styloid 

 process of the temporal bone to the inside of the angle of 

 the jaw. 



These two latter hardly merit the name of ligaments, as 

 they in no way serve to consolidate the articulation ; the 

 first being but a membranous protection to the vessels, and 

 the second an aponeurotic surface of origin of the stylo- 

 glossus muscle. 



An inter-articular fibro-cartilage is seen on opening the 

 joint; it is elliptical and biconcave in shape, and sometimes 

 perforated in the centre : externally it is attached to the 

 external lateral ligament, and internally to the external 

 pterygoid muscle. 



Two synovial membranes are present, forming a shut sac 

 above and below the inter-articular cartilage. 



The condyle of the jaw, with the external pterygoid muscle at- 

 tached, is now to be dislocated and drawn forward. 



The superior and inferior maxillary trunks of the fifth 

 pair of cranial nerves will then be seen issuing from the 

 skull ; the former by the foramen rotundum, and crossing 

 the spheno-maxillary fossa to the canal in the floor of the 

 orbit (p. 35) ; the latter by the foramen ovale, and dividing 

 into two branches; the anterior giving off five muscular 

 branches to the masseter, buccinator, temporal, and exter- 

 nal and internal pterygoid muscles ; the posterior dividing 

 into the auriculo-temporal, inferior dental, and gustatory 

 branches (p. 35). A branch from the internal maxillary 

 artery accompanies each of the nerves sent to the above- 

 named muscles. The otic, or Arnold's ganglion, should be 

 sought for, resting upon the inner surface of the inferior 

 maxillary nerve, just below the foramen ovale. 



The auriculo-temporal nerve, the terminal branches of 

 which have been already dissected (p. 24), separates from 

 the inferior maxillary near the skull; it passes outward 

 beneath the external pterygoid muscle to the inner side of 

 the articulation of the jaw, from which point it ascends 

 5 



