292 THE HUMAN BODY. 



are distributed to most of the muscles which move 

 the eyeball and also to that which lifts the upper eyelid. 



The fourth pair, IV, (pathetiei,) are quite small; each 

 goes to one muscle of the eyeball. 



The fifth pair of cranial nerves, V, (trigeminals,) re- 

 semble the spinal nerves in having two roots, one of which 

 possesses a ganglion (the Gasserian ganglion}. Beyond 

 the ganglion the two roots form a common trunk which 

 divides into three main branches. The first of these, the 

 ophthalmic, is distributed to the muscles and skin over the 

 forehead and upper eyelid; and also gives branches to the 

 mucous membrane lining the nose, and to the integument 

 over that organ. The second division (superior maxillary 

 nerve) of the trigeminal gives branches to the skin over the 

 temple, to the cheek between the eyebrow and the angle of 

 the mouth, and to the upper teeth; as well as to the mu- 

 cous membrane of the nose, pharynx, soft palate and roof 

 of the mouth. The third division (inferior maxillary] is 

 the largest branch of the trigeminal. It is distributed to 

 the side of the head and the external ear, the lower lip 

 and lower part of the face, the mucous membrane of the 

 mouth and the anterior two thirds of the tongue, the lower 

 teeth, the salivary glands, and the muscles which move the 

 lower jaw in mastication. 



The sixth pair of cranial nerves, VI, (alducentes,} are 

 distributed each to one muscle of the eyeball on its own 

 side. 



What is the distribution of the fourth pair? 



Name the fifth pair of cranial nerves. How do they resemble the 

 spinal nerves? What is the ganglion on one root called? Into how 

 many main branches does the common trunk divide? Name the first 

 branch. State its distribution. The second branch. Its distribu 

 tion. The third main brunch. Its distribution. 



Name the sixth pair of cranial nerves. Where do they go? 



