THE HEAD AND NECK 



1 301 



ite ganglion of the facial. It emerges from the petrous part of the tern- 

 oral bone through a small opening (inconstant) close to the hiatus Fallopii, 

 id joins the sympathetic plexus on the middle meningeal artery. 



Deep Petrosal Nerves. — The great deep petrosal nerve is a branch of the carotid 

 lexus of the sympathetic. It joins the great superficial petrosal in the upper 

 irt of the foramen lacerum medium to form the Vidian nerve, which, as 

 ated, passes through the Vidian canal. into the spheno-maxillary fossa, and 

 tins the back part of Meckel's ganglion. 



The small deep petrosal nerve is a branch of the tympanic plexus. It 

 jsses forwards within the processus cochleariformis to the upper part of 

 le foramen lacerum medium, where it joins the carotid plexus of the sympa- 

 letic, and the great deep petrosal nerve, or, it may be, the great superficial 

 Btrosal nerve. In this manner some of its fibres pass in the Vidian nerve 

 ) Meckel's ganglion. 



The Articulations of the Atlas, Axis, and Occipital Bone. 



Atlanto-axial Joints. — These are three in number, and they belong 

 3 the class diarthrosis. One is mesially placed, the articular sur- 

 ices being the atlantal facet on the anterior surface of the odontoid 



Anterior Tubercle 

 of Atlas 



Posterior Sy novial Cavity 

 Transverse Ligament ^ 



Anterior Syno\-ial Cavky 

 , Odontoid Process of Axis 



Superior Articulcir 

 Process of Atlas 



"--Posterior Tubercle of Atlas 



Spinous Process of Axis 



Fig. 540. -The Articulation between the Anterior Arch of the 

 Atlas and the Odontoid Process of the Axis. 



•recess of the axis and the odontoid facet on the posterior surface 

 ■f the anterior arch of the atlas. This joint belongs to the sub- 

 ^vision trochoides or pivot- joint. The other two are placed one on 

 either side, the articular surfaces of each being the inferior articular 

 process of the atlas and the corresponding superior articular process 

 )f the axis. These two joints belong to the subdivision arthrodia. 

 Ligaments. — These are as follows: the transverse ligament, the 

 capsular Hgaments, and the accessory ligaments. Besides these 

 there are the anterior and posterior atlanto-axial ligaments, which 

 ire not directly related to any of the joints. 



