170 AjJ ATOMY OF, THE RABBIT. 



(f) The branches of the maxillary nerve \n. maxillaris), the 

 second division of the trigeminus, traverse the ventral por- 

 tion of Jthe orbit passing forward in company with the internal 

 maxillary artery. They include the sphenopalatine nerve (n. 

 sphenopalatinus) and the infraorbital nerve (n. infraorbitalis). 

 The latter passes forward through the infraorbital groove and 

 foramen to the face. 

 The connections of the sphenopalatine nerve may be examined by, 

 first dividing both nerves at the posterior angle of the orbit; then 

 separating the slender sphenopalatine nerve from the ventral surface of 

 the cord and turning the principal, infraorbital portion forward. A third 

 nerve, the nerve of the pterygoid canal, should remain intact on the 

 orbital wall. 



The sphenopalatine nerve ends in the sphenopalatine ganglion (g. 

 sphenopalatinum) . This is a small, somewhat radiate structure lying 

 immediately behind the sphenopalatine foramen. The nerves proceed- 

 ing from the ganglion include: (1) nasal rami, to the mucous membrane 

 of the nasal cavity; (2) the nasopalatine nerve, which enters the nasal 

 region through the sphenopalatine foramen in company with the nasal 

 rami, and, traversing the nasal septum, passes through the incisive 

 foramen to the anterior portion of the hard palate ; and (3) the anterior 

 palatine nerve, which passes through the pterygopalatine canal to the 

 posterior portion of the hard palate. 



The nerve of the pterygoid canal (n. canalis pterygoidei) is a slender 

 cord which passes backward along the orbital wall from the posterodorsal 

 angle of the ganglion. It lies on the medial side of the sphenopalatine 

 and infraorbital nerves and on the lateral surface -of the palatine bone. 

 Posteriorly it enters the groove representing the pterygoid canal. 



This nerve is composed of two parts, separated posteriorly. One of 

 them, the deep petrosal nerve (n. petrosus profundus), is connected with 

 the sympathetic plexus of the internal carotid artery. The other, the 

 great superficial petrosal nerve (n. petrosus superficialis major) enters the 

 skull at the foramen lacerum, passing into the petrosal bone, in the interior 

 of which it is connected with the trunk of the facial. The nerve con- 

 stitutes the motor root of the sphenopalatine ganglion, the sensory root 

 being that provided by the sphenopalatine nerve. 



The sphenopalatine ganglion is one of several representing the sym- 

 pathetic system in the head, and having motor and sensory roots from 

 the cerebral nerves in addition to their sympathetic connections. The 

 series includes the ciliary ganglion, which lies on the optic nerve, the 

 sphenopalatine ganglion, the otic ganglia, associated with the mandibular 

 nerve, and the submaxillary ganglion, associated with the lingual nerve. 



13. Examination of the middle ear. 



By breaking away the ventrolateral portion of the tympanic bulla 

 and clearing the surface, the structures of the tympanic cavity may be 

 studied. They are chiefly those already described in connection with 

 the skeleton (p. 90), but the following soft parts may be identified. 



