360 CHARLES CLIFFORD MACKLIN 



the facial foramen in a direction outward and slightly forward 

 and enters the ventro-lateral otic recess. Here it becomes 

 associated with the geniculate ganglion from which the great 

 superficial petrosal nerve may be followed forward. Leaving 

 the geniculate ganglion the facial nerve now passes downward 

 and slightly outward over the large cartilaginous bar which 

 unites the pars cochlearis with the pars canalicularis and which is 

 found between the facial foramen above and the vestibular 

 fenestra below; thence it proceeds backward over the incudo- 

 stapedial articulation. It now is to be found just medial to the 

 crista parotica, and runs steeply downward, the relatively small 

 stapedial muscle lying medial to it here. Passing lateral to the 

 upturned end of the cartilage of Reichert, just between the latter 

 and the lower tip of the crista* parotica, it gives off the chorda 

 tympani, and turns suddenly forward, following the line of the 

 shaft of Reichert' s cartilage, being situated shghtly above and 

 lateral to it, and almost immediately lateral to the auditory or 

 Eustachian tube. The relations of the facial nerve at the proxi- 

 mal end of Reichert's cartilage are those shown in Low's ('09) 

 plate, figure 3. The chorda follows its wellknown course through 

 the middle ear anlage. 



It is to be noted that the facial nerve does not go through a 

 secondary facial foramen formed by the connection of the tegmen 

 tjrmpani ventrally with the cochlea, as is the case in the rabbit 

 (Voit), and hence there is no true fovea genicularis in the skull 

 of man in this stage, or, indeed, in any stage, judging from the 

 evidence at hand. 



The slightly younger condition of the cartilage along the ventral 

 margin of the crista parotica would seem to indicate that the 

 facial canal was closing here, but in the Hertwig model it is still 

 ooen at this region. 



The walls of the pars canalicularis are for the most part thin, 

 and composed of mature cartilage. The largest mass of carti- 

 lage is formed by the massa angularis, mentioned above, the 

 ventro-median side of which lies immediately lateral to the fossa 

 subarcuata anterior, while the dorso-lateral side projects outward 

 as the lateral otic eminence. Within the mass, just below the 



