Cranial Nerves. 



143 



CERVICAL. 



1L 



M. scalen. 



487. The Spinal Accessory and Hypoglossal 

 Nerves at the neck. 



The eleventh cranial nerve is the spinal accessory, Nervus 

 recurrens s. accessorius Willisii. It arises from the lateral tract of the spinal cord 

 as low down as the sixth or seventh cervical vertebra by a number of filaments, 

 passes through the Foramen magnum into the skull, leaves it with the pneumo- 

 gastric by the jugular foramen and is divided into an anterior or accessory 

 portion for the Plexus nodosus, and a posterior or spinal portion, which 

 pierces the sterno-cleido-mastoid muscle and terminates in the trapezius (M. cu- 

 cullaris). 



The twelfth cranial or hypoglossal nerve, N. liypoglossus (motor) 

 arises from the Medulla ollongata and leaves the skull by the anterior condyloid 

 foramen. In the neck, where the nerve lies at first behind the vagus, internal 

 carotid artery and internal jugular vein, it curves forwards, then at the M. hyo- 

 glossus upwards, and divides into branches at the posterior margin of the M. mylo- 

 hyoideus, which supply all the muscles of the tongue. Beneath the anterior condyloid 

 foramen it sends communicating branches to the first cervical ganglion of the 

 sympathetic, to the Plexus nodosus of the vagus and to the upper cervical nerves, 

 and somewhat lower the descendens noni branch, It. cervicales descendens, 

 arises, which forms with branches of the second and third cervical nerves, the 

 Ansa liypoglossi. 



