354 



HEAD AND NECK 



the inferior oblique, and the superior oblique. The anterior tubercles and 

 the costal portions of the transverse processes of the third, fourth, fifth, 

 and sixth cervical vertebrae should then be snipped off with the bone forceps. 



Arteria Vertebralis. This is an artery of great importance, 

 for, together with its fellow of the opposite side and the basilar 

 artery, which is formed by their union, it supplies the hind- 

 brain, the mid-brain, and the posterior parts of the cerebral 

 hemispheres, and it helps to supply the spinal medulla. It 



Posterior atlanto- 



occipital membrane 



Posterior branch of 



sub-occipital nerve 



Great occipital nerve 



Vertebral artery. 



Anterior branch 

 of spinal nerves 



Posterior arch of atk 

 Ligamentum nuchas 



Posterior branches of spinal 

 nerves 



Seventh cervical vertebra 



FIG. 141. Dissection of the Ligamentum Nuchae and of the Vertebral 

 Artery in the Neck. 



commences at the root of the neck, as a branch of the first 

 part of the subclavian artery, and it runs upwards, through the 

 transverse processes of the cervical vertebrae, to the base of 

 the skull. It enters the skull through the foramen magnum 

 and unites in the posterior fossa of the cranium, at the lower 

 border of the pons, with its fellow of the opposite side to 

 form the basilar artery. On account of its varying relations 

 it is divided into four parts. The first part, which extends 

 from the subclavian artery to the transverse process of the 

 sixth cervical vertebra, has been seen already (p. 251). It lies 

 between the longus colli medially, the scalenus anterior 



