206 The Spinal Column 



the neck ; it may be dimly felt below, and just in front of the tip of 

 the mastoid process. 



The transverse process of tJic sixth cervical vertebra is easily made 

 out at the root of the neck the carotid tubercle (p. 23). 



ligaments. The bodies of the vertebrae are connected by the 

 strong anteiior and posterior common ligaments, the posterior being 

 lodged within the spinal canal and separated from the central part of 

 the body of each vertebra by the vena basis vertebrae. 



Between the bodies are discs offibro-cartilage, the peripheral parts 

 of which are fibrous, whilst the central parts are pulpy and elastic. 

 The discs form about a fourth of the flexible part of the spine ; they are 

 flattened by prolonged standing. Thus, when a man rises from the bed 

 of sickness he is actually taller, perhaps by a third of an inch, than he 

 w r as when he took to it. The height is also increased by the night's rest. 



The articular processes are connected by capsidar ligaments and 

 synovial membranes, the laminae by the elastic ligamenta subflava, 

 the spinous processes by inter- and supra-spinous ligaments, and the 

 transverse processes by less important fibres. 



The atlas is connected with the axis by two capsidar ligaments and 

 synovial membranes. 



The transverse ligament stretches behind the odontoid process 

 from one lateral mass to the other, sending a slip up to the basilar 

 process of the occiput, and one down to the back of the body of the 

 axis ; thus its shape is cruciform. There is a synovial membrane 

 between the odontoid process and the anterior arch of thef atlas, and 

 another between the process and the transverse part of the cruciform 

 ligament. 



The transverse ligament is less likely to give way from violence than 

 are the adjacent bones, but when it is softened by disease it may sud- 

 denly yield; the head then falling forwards, the medulla is compressed 

 against the back of the odontoid process, and sudden death results. In 

 caries of the high cervical vertebrae absolute rest in bed is the only 

 safe treatment. 



The two anterior atlo-axoid ligaments are really part of the 

 anterior common ligament, and the posterior atlo-axoid is the repre- 

 sentative of the ligamentum subflavum. 



Rotation is the only movement allowed between the atlas and 

 axis ; their joints are supplied by the vertebral arteries and the second 

 cervical nerves. 



The condyles of the occiput articulate with the atlas by capsular 

 ligaments and synovial membranes, and in such a way as to permit of 

 nodding movements only. (Thus, a dumb person expresses ' yes ' at 

 the occipito-atloid joint, and 'no 'at the atlo-axoid.) The occipito- 

 atloid joints are supplied by the suboccipital nerves (p. 143) and the 

 vertebral arteries. 



The two anterior occipito-atloid ligaments represent the anterior 



