166 DISSECTION OF THE NECK. 



tically through the corresponding foramina in the other vertebras. Beyond 

 the atlas, the vessel turns backwards on the neural arch of that bone, and 

 passing beneath the ligament joining the first vertebra with the os occipi- 

 tis, enters the skull through the foramen magnum. In its course through 

 the foramina the artery lies in front of the anterior trunks of the cervical 

 nerves, except those of the first and second the former of which crosses 

 on the inner, and the latter on the outer side. The vessel is accompanied 

 by a vein, and by a plexus of nerves of the same name. 



In the neck the artery furnishes small twigs to the surrounding muscles, 

 the spinal canal, and the spinal cord. 



The vertebral vein begins by small radicles in the occiput, and in the 

 muscles of the back of the neck, and enters the aperture of the atlas, where 

 it receives sometimes a vein from the skull through the posterior condyloid 

 foramen of the occipital bone. Accompanying the artery, the vein tra- 

 verses the apertures between the transverse processes, and ends in the 

 subclavian vein. 



In its course it is joined by branches from the internal and external 

 spinal veins ; its other branches are described at p. 78. 



The vertebral plexus of nerves is derived from the inferior cervical 

 ganglion of the sympathetic (p. 117). It surrounds the artery, and com- 

 municates with the spinal nerves as high as the third or fourth. 



SECTION XIX. 



LIGAMENTS OF THE VERTEBRAE AND CLAVICLE. 



Directions. On the remaining part of the spine, the ligaments connect- 

 ing the cervical vertebrae to each other and to the occipital bone are to be 

 learnt. 



Dissection. Disarticulate the last cervical from the first dorsal verte- 

 bra. Then remove altogether the muscles, vessels, nerves, and areolar 

 tissue and fat from the cervical vertebrae. By sawing through the occipi- 

 tal bone, so as to leave only an osseous ring behind the foramen magnum, 

 the ligaments between the atlas and the occipital bone can be more easily 

 cleaned. 



The COMMON LIGAMENTS attaching together the cervical vertebrae are 

 similar to those uniting the vertebrae in other parts of the spine, viz., an 

 anterior and a posterior common ligament; bands between the lamina? and 

 spines ; capsular ligaments and synovial membranes for the articulating 

 processes ; and an intervertebral ligament between the bodies of the bones. 



Directions. The common ligaments will be best seen on the dorsal or 

 lumbar portions of the spine where they are more fully developed ; their 

 preparation and description will be found at the end of the thorax, with 

 the description of the ligaments of the spine. Should the student examine 

 them in the neck, to see their difference in this region of the spine, he 

 should leave uncut the neural arches of the three highest cervical vertebrae, 

 to which special ligaments are attached. 



SPECIAL LIGAMENTS unite the first two cervical vertebrae to each other 

 and to the occipital bone : some of these are external to, and others within 

 the spinal canal. 



