156 



THE ARTICULATIONS OF THE TRUNK AND HEAD. 



Two synovial cavities are placed one in front of and the other behind the 

 odontoid process ; the first of these is situated between the process and the anterior 

 arch of the atlas ; the other, which is the more extensive of the two, is between the 

 process and the transverse ligament. 



The lateral or alar odontoid or check ligaments are two short but very 



Fig. 181. TRANSVERSE SECTION SIMILAR TO THAT SHOWN iff 



FIG. 179, THE CRUCIFORM LIGAMENT HAVING BEEN RE' 



MOVED. (Allen Thomson. ) ^ 



4, alar odontoid ligament ; 5, accessory atlanto-axial liga- 

 ment ; 6, 7, capsular ligaments of the occipito-atlantal and 

 the atlanto-axial articulations ; 9, odontoid process ; _ 9, 9' r 

 middle odontoid ligament. 



strong bundles of fibres, which extend from the- 

 sides of the summit of the odontoid process out- 

 wards and a little upwards to be implanted into- 

 the rough impression on the inner side of each 



SPHENOIDAL. 

 SINUS 



ANTERIOR 

 COMMON 

 UIGAMELNT 



POST. COMMON UG1 

 UIG. DCNTICULATUM 



Fig. 182. MEDIAN SECTION OF THE FIRST THREE CERVICAL VERTEBRA AND PART OF THE OCCIPITAL 

 BONE, WITH THEIR LIGAMENTS, &c. (Drawn by T. W. P. Lawrence.) 



V to XII, fifth to twelfth cranial nerves ; C I to C IV, first to fourth cervical nerves. 



condyle of the occipital bone. Some of the upper fibres of the two ligaments are 

 usually continuous across the middle line. 



The middle odontoid or suspensory ligament is a small cord which passes 



