188 



THE ARTICULATIOXS 



(<•) The Li(;ami:xt.s uniting tup: Occiput and Axis 



The following ligaments unite bones not in contact, and are to be seen from the 

 intt'iior of the canal after removing the posterior arches of axis and atlas and 

 posterior ring of the foramen magnum: — 



1. The occipito-cervical. 



2. The crucial. 



3. Two lateral odontoid or check. 



4. The central odontoid or suspensory, 



The occipito-cervical or cervico-basilar ligament (figs. 196, 197, and 198) 

 consi.sts of a vcrv strong l)and of lil)rcs. connected l)elow to the upper part of the 

 hody of tlie third vertel^ra and lower ])art of the l)ody of the axis as far as the root 

 of the odontoid i)rocess. It is narrow below, but widens out as it ascends, to be 



Fig. 197.— Thk Siperficiai, Layer of the Posterior Common Vertebral Licjamext 



HAS been REMOVKI) TO SHOW ITS DEEP OR SHORT FIBRES. THESE DEEP FIBRES FORM 



THE Occipito-cervical Ligament. 



Atlanto-asoid- 

 eau capsular 

 ligament 



Occipito-cervi- 

 cal ligament, 

 i.e., the deep 

 stratum of the 

 posterior com- 

 mon vertebral 

 ligament 



Transverse process of atlas 



fastened to the basilar groove of the occiput. Laterally, it is connected with the 

 accessory fibres of the atlanto-axoidean capsule. It is really only the upward pro- 

 longation of the deep stratum of the posterior common ligament, the superficial 

 fibres of which run on to the occipital bone without touching the axis, thus giving 

 rise t<» two strata. It is in relation in front with the crucial ligament. 



Till' crucial ligament lias l)een already described (see page 186). 



The lateral occipito-odontoid or check ligaments (figs. 195 and 198) are 

 two strong rounded cords, which extend from the sides of the apex of the odontoid 

 ])rocess, transversely outwards to the inner edge of the anterior portion of the 

 occii)ital condyles. They are to be seen immediately above the upper border of the 

 transverse ligament, which they cross oblicjuely owing to its forward curve at its 

 attachments to the atlas. Some of their fibres occasionally run across the middle 

 line from one check ligament to the other. At the odontoid ]>rocess they are 

 connected with the atlanto-odontoid capsule, and at the condyles they strengthen 

 the occi])it()-atlantal ca])sular ligaments. 



The central odontoid or suspensory ligament (figs. 195 and 198) consists of 



