1304 



A MANUAL OF ANATOMY 



between the occipital condyles. In the median line it is rendered 

 thick by the addition of a stout, round bundle of fibres, representing 

 the accessory ligament, the fibres of which for the most part are 

 attached below to the anterior tubercle of the atlas, but some of 

 them are prolonged into the thickened anterior accessory part of 

 the anterior atlanto-axial ligament. 



The posterior atlanto-occipital ligament, broad, thin, and mem- 

 branous, is attached inferiorly to the upper margin of the posterior 

 arch of the atlas, except in the region of the vertebrarterial grooves, 

 and superiorly to the lower margin of the foramen magnum behind 

 the occipital condyles. Over each vertebrarterial groove of the 

 atlas this ligament forms an arch, beneath which the vertebral artery 

 and suboccipital nerve pass. 



Posterior Occipito-axial Ligament 



(Membrana Tectoria) 



Superior Crus of Vertical Part 



of Cruciform Ligament 



Anterior Margin of jv. 



Foramen Magnum \ |>" 



Odontoid Process of Axis 



- 1.1 A ^« 



.Basilar Groove of Occipital Bone 

 •' , Middle Odontoid or Suspensory 



;•>,'' Ligament 



, Anterior Condylar Foramen 

 _ Lateral Odontoid or 

 Check Ligament 



Occtpito-atlai> 



tal Joint 

 (capsule) 



Atlanto-axial 

 Joint (opened). 



Spinous Process of Axis 



Fig. 543. — The Occipital, Atlantal, and Axial Ligaments (Deep 

 Posterior View). 



Occipito-axial Ligaments. — These are as follows: the posterior 

 occipito-axial hgament; the lateral odontoid, or check, ligaments; 

 the middle odontoid, or suspensory, ligament; and the vertical 

 portion of the cruciform ligament. 



The posterior occipito-axial ligament, also called the membrana 

 tectoria, is a broad membranous band, which is attached inferiorly 

 to the posterior surface of the body of the axis, where it is con- 

 tiiyious with the fibres of the posterior common ligament of the 

 bodies of the vertebrae, and superiorly to the posterior part of the 

 basilar groove of the occipital bone. It covers the odontoid pro- 

 cess of the axis and the odontoid and cruciform ligaments, hence the 

 name membrana tectoria. 



