306 



LABORATORY MANUAL. OF HUMAN ANATOMY 



of the N. intermedius is reached, it will be recognizable as a 

 swelling at the point where the N. facialis bends backward to 

 enter the tympanic portion of the facial canal of Fallopius. 

 Avoid injury to the delicate nerve threads connected with the 

 ganglion geniculi. 



Push a fine pin upward through the stylomastoid foramen 

 (foramen stylomastoideum) to ascertain the course of the distal 

 portion of the canalis facialis [Fallopii]. This can be opened 

 by first removing the mastoid process by a coronal saw-cut in a 

 plane just behind the foramen stylomastoideum. When this cut 

 has gone as deep as the foramen, make a second cut at right 

 angles to it, that is, a sagittal saw-cut, to meet the extremity 



FIG. 133. 



Gang, 

 genie. 



N. staped 



- 



N. petros. superfic. maj. 



.N. petros. superfic. 

 min. 



... N. ophth. 



%^N. max. 



N. to M. tens. tymp. 

 Gang, oticum 



Chorda tympani 



-N. auric, temp. 

 -N. lingualis 



--N. alveol. inf. 



Chorda tympani (after Hirschfeld). (From Poirier et Charpy, 

 Traite d'Anat. hum., Paris, 1899, t. iii., 3, p. 847, Fig. 483.) 



of the first cut. Eemove the bone thus excised and open the rest 

 of the facial canal with a chisel. 



Study the direction followed by the N. facialis in each of its 

 four stages. Examine the following : 



Facial Nerve (N. facialis). (Vide Fig. 133.) 

 Note- 



(a) Knee of the facial nerve (geniculum N. facialis) and the ganglion at 



the knee (ganglion geniculi), which really belongs to the N. inter- 

 medius. 



(b) Nerve to stapedius muscle (N. stapedius). 



(c) Ramus anastomosing with the tympanic plexus (ramus anastomoticus 



cum plexu tympanico) (0. T. tympanic branch). This helps to 

 form the lesser superficial petrosal nerve (N. petrosus superficialis 

 minor). 



