276 



THE ARTICULATIONS, OR JOINTS 



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

 vertebral artery and suboccipital rierve. The fibrous band which arches over the 

 artery and nerve sometimes becomes ossified. The ligaments are in relation, 

 behind, with the Recti postici minores and Obliqui superiores; in front, with the 

 dura of the vertebral canal, to which they are intimately adherent. 



POSTERIOR OC- 



CIPITO-ATLANTAL 



LIGAMENT 



POSTERIOR OC- 



CIPITO-ATLANTAL 



LIGAMENT 



POSTERIOR 



ATLANTO-AXIAL" 



LIGAMENT 



TRANSVERSE 

 PROCESS OF 

 ATLAS 



TRANSVERSE 

 PROCESS OF 

 AXIS 



FIG. 225. Occipital bone, first and second cervical vertebra* with ligaments from behind. (Spalteholz.) 



The capsular ligaments (capsulae articulares) (Fig. 227) surround the condyles 

 of the occipital bone, and connect them with the articular processes of the atlas; 

 they consist of thin and loose capsules, which enclose the synovial membranes 

 of the articulations. 



Synovial Membranes. There are two synovial membranes in this articulation, one lining the 

 inner surface of each of the capsular ligaments. These occasionally communicate with that 

 between the posterior surface of the odontoid process and the transverse ligament. 



FIG. 226. Articulation between odontoid process and atlas. 



Movements. The movements permitted in this joint are flexion and extension, which give 

 rise to the ordinary forward and backward nodding of the head. Slight lateral motion to one 

 or the other side may also take place. When either of these actions is carried beyond a slight 

 extent, the whole of the cervical portion of the spine assists in its production. Flexion is mainly 

 produced by the action of the Rectus capitis anticus major et minor and the Sternomastoid 

 muscles; extension by the Rectus capitis posticus major et minor, the Obliquus superior, the 



