6o 



APPLIED ANATOMY. 



Excision of the Lingual and Inferior Dental Nerves. Neuralgia in- 

 volving the face below the line of the mouth, the lower teeth, and side of the tongue 

 requires the removal of the inferior dental and lingual nerves. To do this, a curved 

 incision following the lower edge of the mandible is made. It ends anteriorly in 

 front of the mandibular foramen, and posteriorly it stops a centimetre below the ear to 

 avoid wounding the facial nerve. The masseter muscle is raised from the bone, and, 

 with the parotid gland, is drawn up. The ramus of the jaw is trephined in its middle, 

 rather high up toward the coronoid notch. The outer table of bone is then to be 

 chiselled off, from the trephine opening as far down as the mental foramen. A 

 delicate, curved, haemostatic forceps is then made to grasp both nerves through the 



Lingual nerve 



Internal pterygoid muscle 

 Mandibular net 



FIG. 6S. Excision of the lingual and mandibular (inferior dental) nerves. 



trephine opening, and on rotating very slowly the nerves are wound around the for- 

 ceps and are gradually torn loose from the base of the skull above to their ultimate 

 branches below (see Fig. 68). 



Operations on the Gasserian Ganglion. The Gasserian ganglion lies in 

 its capsule, formed by a splitting of the dura, on the anterior surface of the apex of 

 the petrous portion of the temporal bone and on the root of the greater wing of the 

 sphenoid. From its posterior extremity, which rests on the ridge separating the 

 anterior and posterior surfaces of the petrous portion of the temporal bone, to the 

 foramen rotundum anteriorly is 2.5 to 3 cm. (i to i ^ in.). The foramen ovale, which 

 transmits the third or mandibular branch is midway between these two points, and 

 corresponds on the outside of the skull to the eminentia articularis or root of the 

 zygoma. Therefore, in removing the ganglion one works not only inward but also 

 backward. Rose first operated on the ganglion from below. He removed the 

 zygoma and coronoid process, ligated the internal maxillary artery, and trephined 

 the skull in front of the foramen ovale. This operation was succeeded by that of 

 Hartley and Krause. They went in through the temporal fossa. A large horseshoe- 

 shaped flap, with its base above the zygoma, was cut and deepened with chisels 

 through the bone to the dura. This was elevated by breaking across its base, and turn- 

 ing it down. The dura was then lifted from the base of the skull, and the maxillary 

 and mandibular nerves recognized as they passed into the round and oval foramina. 

 The capsule having been incised, these were seized with forceps, and as much of the 

 ganglion as possible torn away. 



Other surgeons, like Doyen, Quenu, Poirier, and Gushing, have combined these 

 pterygoid and temporal routes. The bone flap, as made by Hartley and Krause, 



