CEPHALIC NERVES PORT10 DURA, GLOSSO -PH ARYNGEAL. 619 



the Corpora Quadrigemiua; a fact of considerable physiological importance, 

 as will hereafter appear. The chief actions of a purely reflex, nature to which 

 this group of nerves ordinarily ministers, are the government of the diameter 

 of the pupil, which is accomplished through the Third, pair; and the rolling 



The distribution of the Facial Nerve, and the branches of the Cervical Plexus : 1. The facial nerve, 

 escaping from the stylo-mastoid foramen, and crossing the ramus of the lower jaw; the parotid gland 

 has been removed in order to show the nerve more distinctly. 2. Tbe posterior auricular branch : the 

 digastric and stylo-mastoid filaments are seen near the origin of this branch. 3. Temporal branches, 

 communicating with (4) the branches of the frontal nerve. 5. Facial branches, communicating with 

 (6) the infra-orbital nerve. 7. Facial branches, communicating with (8) the mental nerve. 9. Cervico- 

 facial branches, communicating with (10) the superficialis colli nerve, and forming a plexus (11) over 

 the subniaxillary gland. The distribution of the branches of the facial in a radiated direction over 

 the side of the face, constitutes the pes anserinvis. 12. The auricularis magnus nerve, one of the 

 ascending branches of the cervical plexus. 13. The occipitalis minor, ascending along the posterior 

 border of the sterno-mastoid muscle. 14. The superficial and deep descending branches of the cervical 

 plexus. 15. The spinal accessory nerve, giving off a branch to the external surface of the trapezius 

 muscle. 16. The occipitalis major nerve, the posterior branch of the second cervical nerve. 



of the eyeball beneath the upper lid during sleep, as well as in the efforts 

 of sneezing, coughing, etc. But irregular movements of the eyeballs, which 

 must be referred to the same group, are continually seen to accompany 

 various abnormal forms of convulsive action. 



492. The Portio Dura of the 7th pair, or Facial Nerve, containing about 

 4000 to 4500 nerve-fibres, was shown by Bell to be a 'motor nerve, chiefly dis- 

 tributed to the muscles of the face ; it has hence been termed the Nerve of ex- 

 pression. In its passage through the Aqueductus Fallopii, it presents a gangli- 

 form enlargement, which is connected by the N. petrosus superficialis major 

 with the spheno-palatine ganglion of the 5th, and by the N. petrosus super- 

 ficialis minor with the otic ganglion. By these branches the palatine muscles 

 supplied by these ganglia receive their motor power, and some sensory fibres 

 enter the facial, thus accounting for its sensibility when cut at its exit from 

 that canal. It is also connected with the tympanic nerve of Jacobson pro- 

 ceeding from the glosso-pharyngeal, with the auricular of the Pueumogastric, 

 and with the upper cervical nerves. The Portio Dura, besides the muscles 

 of the face, supplies the stapedius, the auricular, occipital, stylohyoid, and 



