DISSECTING MANUAL. 



the naso-palatine nerve, grooving the vomer, to the incisive 

 foramen. [812] 



Internal Carotid. Ascending under the parotid gland and 

 finally getting under the external carotid, it runs through the 

 carotid canal to the cranial cavity. Its further course and 

 branches are described with the arteries of the cranial cavity 

 (page 47). [813] 



Vertebral. Arising from the upper and back part of the 

 subclavian this ascends (first part) between the Scalenus an- 

 ticus and Longus colli; then (second part) traverses the fora- 

 mina in the upper six cervical transverse processes; and 

 then (third part) curves backward in a groove on the upper 

 surface of the posterior arch of the atlas and runs under the 

 oblique ligament of the atlas into the spinal canal. Then 

 (fourth part) piercing the spinal dura it ascends to the cra- 

 nium, inclining inward to the front of the medulla and joining 

 its fellow at the lower border of the pons to form the basilar. 

 Its branches are : muscular; spinal, running through the inter- 

 vertebral foramina to the anterior and posterior spinal ar- 

 teries; anastomotic, to the princeps cervicis and profunda 

 cervicis; meningeal, to the posterior fossa; posterior spinal, 

 descending through the foramen magnum, at the side of the 

 medulla and cord, in front of the posterior nerve roots; an- 

 terior spinal, descending in front of the medulla and uniting 

 with its fellow in front of the anterior fissure of the cord; and 

 posterior inferior cerebellar, to the vallecula cerebelli. [818] 



Thyroid Axis. Arising from the subclavian internal to the 

 Scalenus anticus, this ascends and soon divides into three 

 branches, as follows: [823] 



The inferior thyroid ascends behind the carotid sheath to the 

 thyroid body. Its branches are: muscular; ascending cervi- 

 cal, ascending between the Scalenus anticus and Rectus capitis 

 anticus major; ossophageal, to the oesophagus; tracheal, to 

 the trachea; inferior laryngeal, accompanying the inferior 

 laryngeal nerve; ascending terminal, to the posterior and 



[82] 



