NERVUS FACIALIS OF ALBINO MOUSE 95 



lunare. After a short course it bends at almost a right angle and 

 passes medially, ventral to the nervus trigeminus, and ventral to 

 the internal carotid artery and the sympathetic plexus which 

 surrounds it. At a point just medial to the artery the nerve 

 bends anteriorly and is joined along its medial side by the nervus 

 petrosus profundus, the two uniting to form the nervus canalis 

 pterygoidei. 



A. Nervus petrosus profundus. The nervus petrosus profun- 

 dus, in the mouse, is formed by two small bundles of fibers from 

 the internal carotid plexus. It does not have a separate course 

 for the fibers join the great superficial petrosal nerve immediately 

 after leaving the plexus and while still in relation to the artery. 



The fibers composing this nerve can readily be followed to the 

 interior of the superior cervical sympathetic ganglion. Along 

 the nerve of the pterygoid canal they occupy, at first, a position 

 on its medial side Farther anteriorly, however, they become 

 intermingled to such an extent with those from the great super- 

 ficial petrosal nerve that the fibers from the two sources cannot 

 be separately identified. 



B. Nervus canalis pterygoidei. In mice, the internal carotid 

 artery enters the cranium and the nerve of the pterygoid canal 

 leaves it through a slit-like fissure between the tympanic and 

 periotic bones (eustachian aperture) . From this fissure the nerve 

 passes anteriorly and slightly medially along the ventral surface 

 of the body of the sphenoid bone. One of the pharyngeal muscles 

 (probably the salpingo-pharyngeus), the pharyngeal opening of 

 the auditory tube and a mass of glands lie ventral to it. At the 

 anterior border of the opening of the auditory tube the muscle 

 and glands disappear and the nerve lies between the bone and 

 the mucous membrane of the nasal cavity. At this place the 

 pterygoid process extends ventrally to the soft palate, the nerve 

 lying medial to it where it fuses with the body of the bone above. 

 In this position the nerve extends anteriorly for some distance 

 finally passing laterally through a foramen into the most posterior 

 part of the orbit. 



The nerve of the pterygoid canal is, at first, flattened dorso- 

 ventrally becoming circular in outhne more anteriorly with the 



THE JOCRNAL OF COMPARATIVE NECROLOGY, VOL. 30, NO. 1 



