3 io 



ANATOMY AND PHYSIOLOGY 



it is the sensory nerve of the air passages from the larynx down, 

 and of the alimentary tract from the pharynx down. 



The eleventh, or spinal accessory, is traced from the medulla 

 through the jugular foramen, with the ninth and tenth. It 

 supplies the sterno-mastoid and trapezius muscles with motor 

 nerves. (A portion of it is accessory to the vagus.) 



The twelfth, or hypo-glossal (under the tongue), supplies the 

 muscles of the tongue and those connecting it with the jaw and 

 hyoid bone; also the ribbon muscles in front of the neck. 



Summary 



The nerves of the cerebro-spinal system are distributed to 

 all voluntary muscles, and to all sensitive structures, as skin, mucous 

 membranes, lining of joints, and periosteum. They are the nerves 

 of conscious life. 



CRANIAL NERVE SUPPLY TO CERTAIN MUSCLE GROUPS 



Certain associated movements of the orbital muscles are of interest. 

 The central connections are so arranged that the external rectus 

 of one eye and the internal rectus of the other move together; 



