(>^ DISSECTION OF THE NECK. 



one of the intrinsic muscles of the larynx, the crico- 

 thyroid. The superior laryngeal anastomoses with 

 the inferior laryngeal by a large branch passing be- 

 neath the wing of the thyroid cartilage. 



11. Somewhat posterior to the origin of the superior 

 laryngeal the sympathetic trunk separates from the 

 vagus. Follow it forward a short distance until it 

 ends in the super i 07^ cervical ganglion. 



Just anterior to its ganglionic enlargement the vagus 

 enters the skull. Emerging at about the same point 

 the following cranial nerves can be found : 



12. The Hypoglossal, or 12th Cranial Nerve, is very 

 large ; it runs forward beneath the digastric and mylo- 

 hyoid muscles to enter the tongue, to which it supplies 

 motor fibres. It leaves the skull through the anterior 

 condylar foramen. 



a. The Descendens Hypoglossi, a branch of the 

 hypoglossal, arises from the convex border of the 

 loop made by the hypoglossal and passes posteriorly 

 along the neck superficial to the vagus and carotid ; 

 in its course it soon unites with a branch of the first 

 cervical spinal nerve, and from the common trunk 

 branches are given to the sterno-thyroid and sterno- 

 hyoid muscles. The nerve is very long, reaching to 

 the posterior third of the neck. 



13. The Spinal Accessory, or nth Cranial Nerve, 

 leaves the skull through the jugular foramen in com- 

 pany with the vagus and glosso-pharyngeal ; it runs 

 posteriorly upon the sterno-mastoid muscle, within 

 which it soon disappears. It supplies this and other 

 muscles of the neck with motor fibres. 



14. The Glosso-pharyngeal, or 9th Cranial Nerve, 

 appears in the same place close to the vagus; it turns 

 inward to the mid-line and disappears in the muscles 



