THE INFEEIOE MAXILLARY NERVE. 545 



an acute angle by the chorda fympani, a small branch connected with 

 the facial nerve, which descends fi"om the inner end of the Glaserian 

 fissure. It then passes between the internal pterygoid muscle and the 

 lower maxilla, and is inclined obliquely inwards to the side of the tongue, 

 over the upper constrictor of the pharynx, (where this muscle is attached 

 to the maxillary bone,) and above the deep portion of the submaxillary 

 gland. Lastly, the nerve crosses Wharton's duct, and is continued along 

 the side of the tongue to the apex, in contact with the mucous mem- 

 brane of the mouth. 



(ff) Cemmiinicatvirj hi'ayichcs are given to the sulimaxillary g^ang-lion. at the 

 place where the nerve is in contact with the submaxillary gland. Others form a 

 plexus with branches of the hj-poglossal ners'e at the inner border of the hypo- 

 glossus muscle. 



(Z*) Branchca to the mvcoits mcmhrnnc of the mouth are given from the nerve 

 at the side of the tongue, and supply also the gums. Some delicate filaments are 

 likewise distributed to the substance of the sublingual gland. 



(<•) The lingual or terminal branches perforate the muscular structure of the 

 tongue, and divide into filaments, which are continued almost vertically upwards 

 to the conical and fungiform papilla?. Xear the tip of the tongue the branches 

 of the gustatory and hypoglossal nerves are united. 



Inferior Dental Nerve. — The inferior dental nerve is the largest of 

 the three branches of the lower maxillary nerve. It descends under 

 cover of the external pterygoid muscle, behind and to the outer side of 

 tlie gustatory nerve, and, passing between the ramus of the jaw and the 

 internal lateral ligament of the temporo-maxillary articulation, enters 

 the inferior dental canal. In company with the dental artery, it pro- 

 ceeds along this canal, and supplies branches to the teeth. At the 

 mental foramen it l)ifurcates ; one part, the incisor branch, being 

 continued onwards within the bone to the middle line, while the other, 

 the much larger laliial branch, escapes by the foramen to the face. 



"When about to enter the foramen on the inner surface of the ramus 

 of the jaw, the inferior dental nerve gives off the slender my lo-hyoid branch. 



(c/) The mi/h-loidul hmnch is lodged in a groove on the inner surface of the 

 ramus of the maxillary bone, in which it is confined by fibrous membrane, and is 

 distributed to the lower or cutaneous surface of the mylo-hyoideus and to the 

 anterior belly of the digastric muscle. This nerve may be traced back within 

 the sheath of the inferior dental to the motor portion of the inferior maxillary nerve. 



(Jj) The dental hrnnchr.s supplied to the molar and bicuspid teeth coiTespond to 

 the number of the fangs of those teeth. Each branch enters the minute foramen 

 in the extremity of a fang, and temiinates in the pulp of the tooth. Not un- 

 frequently a collateral branch supplies twigs to several teeth. 



{c) The incixnr hrnncli has the same direction as the tninkof the nerve : it ex- 

 tends to the middle line from the point of origin of tire labial branch, and sup- 

 plies nerves to the canine and incisor teeth. 



{()) The Inhialovmrntdl branch emerging from the bone by the foramen on the 

 outer surface, divides beneath the depressor of the angle of the mouth into two parts. 



One of these, the outer division, communicating with the facial nerve, sup- 

 plies the depressor anguli oris and orbicularis oris muscles, and the integument of 

 the chin. 



The inner portion, the larger of the two, ascends to the lower lip beneat^-i the 

 depressor labii inferioris muscle, to which it gives filaments : the greater number 

 of the branches end on the inner and outer surfaces of the lip. These inner 

 branches assist only slightly in forming the plexus of union with the facial nerve. 



Varieties. —The lingual has been observed to tovm a single trunk -with the 



inferior dental as far as the dental foramen. The infeiior dental sometimes has 



one or two accessory roots from other divisions of the inferior maxillary. The 



most common of these is one which arises from the stem of the inferior maxil- 



VOL. I. K N 



