SPECIAL VERTEBRAL ARTICULATIONS. 131 



5PECIAL VERTEBRAL ARTICULATIONS. 



Occlpito-atloid Articulation. — This joint is formed by the 

 occipital condyles and the glenoid cavities of the atlas, and 

 possesses five ligaments — one capsular, two lateral or styloid, 

 superior suspensory, inferior suspensory. This joint is a true 

 one, having two synovial membranes — one for each condyle. The 

 .styloid ligaments pass from the base of the occipital styloid 

 prc3esses to the sides of the atlas. The superior suspensory or 

 occipito-atloid is very broad, and consists of fibres, which cross 

 each other, e3^,tending from the superior margin of the foramen 

 magnum to the notch on the anterior border of the atlas. The 

 inferior siispensory ov occijpito-atloid stretches from a notch on 



Fia. 46. 



Neural canal of first three cervical vertebrae, opened from above 

 to show the internal ligaments. The occiput and foramen mag- 

 Qum are seen to the right, b, The odontoid ligament; a, The 

 occipito-atioid portion (long odontoid) ; c, Superior common 

 ligament ; d, Posterior articular cavity of a vertebral centrum. 



the anteiv-inferior part of the atlas to the inferior margin of the 

 foramen magnum; it is thin and membranous. The capsular 

 ligament passing completely round the joint, becomes blended 

 with the other ligaments. The latter are sometimes considered 

 as mer--^ enlargements or strengthenings of the capsular ligament, 

 which, this view being taken, would then become the only liga- 

 ment of the joint. This joint allows of flexion, extension, 

 circumduction, and lateral motion. 



Atlo-axoid Articulation. — This joint is formed by the oppo- 

 sing articular f^urfaces of the atlas and axis, and is also a true 

 joint. The atlo-axoid ligaments are the capsular, the superior, 

 the inferior, and the odontoid. The capsular is very broad 

 superiorly, where it closes the atlo-axoid space. The superior 

 ligament passes from the supero-posterior part of the ring 

 of the atlas to the neural spine of the dentata. The inferior 

 joins the inferior spines of the two bones. The odontoid springs 



