194 



ARTICULATIONS. 



1. ARTICULATION OF THE ATLAS WITH THE OCCIPITAL BONE. 



This articulation is a double arthrodia. Its ligaments are the 



Two Anterior Occipito-atloid. 

 Posterior Occipito-atloid. 

 Two Lateral Occipito-atloid. 

 Two Capsular. 



Of the Two Anterior Ligaments (fig. 117), the most superficial is a strong 

 narrow, rounded cord, attached, above, to the basilar process of the occiput; 

 below, to the tubercle on the anterior arch of the atlas : the deeper ligament is a 

 broad and thin membranous layer, which passes between the anterior margin of 

 the foramen magnum above, and the whole length of the upper border of the 

 anterior arch of the atlas below. This ligament is in relation, in front, with the 

 Eecti antici minores ; behind, with the odontoid ligaments. 



The Posterior Occipito-atloid Ligament (fig. 118) is a very broad but thin mem- 

 branous lamina, intimately blended with the dura mater. It is connected, above, 

 to the posterior margin of the foramen magnum; below, to the upper border of 

 the posterior arch of the atlas. This ligament is incomplete at each side, and 

 forms, with the superior intervertebral notch, an opening for the passage of the 

 vertebral artery and suboccipital nerve. It is in relation, behind, with the Recti 

 postici minores and Obliqui superiores; in front, with the dura mater of the spinal 

 canal, to which it is intimately adherent. 



Fig. 120. Occipito-axoid and Atlo-axoid Ligaments. Posterior View. 



Mir Vertical fiorfitn 



&/OOOMTOIO LICTf 



OCCifTOJ CAPSUlAR LIC 7 ,V 



ATtOiO ( Synovia I membrane 



LICT a 



aiemirune 



The Lateral Ligaments are strong fibrous bands, directed obliquely upwards 

 and inwards, attached, above, to the jugular process of the occipital bone ; below, 

 to the base of the transverse process of the atlas. 



The Capsular Ligaments surround the condyles of the occipital bone, and con- 

 dect them with the articular surfaces of the atlas ; they consist of thin and loose 

 capsules, which inclose the synovial membrane of the articulation. The synovial 

 membranes between the occipital bone and atlas communicate occasionally with 



