NERVOUS SYSTEM 67 



from the jugular foramen of the skull, and is dis- 

 tributed to the root of the tongue, soft palate, and 

 pharynx. 



10. The Vagus Nerve (X.) also emerges from the 

 jugular foramen. It has two ganglia, one within 

 the skull, at the point where it enters the foramen, 

 and another, outside the skull, a short distance be- 

 yond the foramen. The nerve passes down the 

 neck, between the internal jugular vein and the 

 carotid artery, enters the thorax, and there passes 

 along the oesophagus and posterior mediastinum. 

 It sends branches to the following organs : phar- 

 ynx, larynx, heart, lungs, oesophagus, stomach, 

 liver, and spleen. 



11. The Spinal Accessory Nerve (XI.) passes ante- 

 riorly along the side of the spinal cord, enters the 

 skull by the foramen magnum, and again emerges 

 from the jugular foramen in two branches. One 

 branch fuses with the vagus nerve at the first gan- 

 glion of the latter ; the other branch is distributed 

 to the sterno-mastoid and trapezii muscles. 



12. The Hypoglossal Nerve (XII.) leaves the skull 

 by the anterior condyloid foramen, passes back to 

 the lower side of the digastric muscle, then for- 

 ward above the hyoid bone to the under side of 

 the tongue. 



SPINAL CORD. 



The Spinal Cord is the posterior continuation of 

 the medulla oblongata, which lies in the neural 



