MECKEUS GANGLION. IT)-) 



The palpebral branches, the smallest of the tenuinul divisions of the nerve, 

 pierce the origin of the levator labii superioris, and turn upwards around the 

 lower border of the orl)iculai-is ])al]iebrarum. They are usually two in numl)er, an 

 external and an internal; they ramify in the integument of the lower eyelid. 



The terminal branches of the maxillary division coiununiicatc fn^ely with the 

 infraorbital brand) of th(^ facial, forming the infraorbital plexus. Tiie plexus is 

 placed under cover of the levator la)>ii sujx'rioris. 



Meckel's Ganglion 



The spheno-palatine, nasal, or Meckel's ganglion is a small reddish-grey 

 body wliich is situated in the spheno-maxillary fossa. It is triangular in form, 

 llattened at the sides, and measures about one-fifth of an inch in its longest diameter. 

 It is provided with three roots, a motor and a sympathetic, which reach it through 

 the Vidian nerve, and a sensory root from the maxillary nerve. The latter root is 

 in tlie form of two stout twigs, wliich are described as the spheno-})alatine nerves. 



Roots. — Tile great superficial petrosal nerve is the motor root of the ganglion. 

 It arises from the geniculate ganglion of the facial nerve within the aqueduct of 

 Fallopius, and enters the cranial cavity by traversing the hiatus Fallopii. It then 

 runs forwards and inwards in a groove in the petrous portion of the temporal bone, 

 and, after passing under the Gasserian ganglion, enters an ol)lique canal in the 

 cartilage which occupies the foramen lacerum medium. Having reached the 

 posterior opening of the Vidian canal, it unites Avith the great deep petrosal nerve 

 to form the Vidian nerve. 



The great deep petrosal nerve is of a grey colour and is soft in consistence. 

 It arises from the carotid ])lexus of the sympathetic close to the intracranial termi- 

 nation of the carotid canal, traverses a canal in the cartilage, which occu])ies the 

 foramen lacerum medium, and joins the Vidian nerve. 



The Vidian nerve runs forwards through the canal of the same name, accom- 

 panied l»y the N'idian artery, and enters the spheno-maxillary fossa, where it ends 

 in the posterior angle of Meckel's ganglion. While within the canal the Vidian 

 nerve furnishes nasal twigs to the mucous membrane of the posterior part of the 

 roof of the nose. They may be regarded as superior nasal nerves, which, after 

 leaving ^Meckel's ganglion, have become associated with the Vidian nerve for a ])art 

 of their course. 



Branches. — The V)ranches of Meckel's ganglion are classified into (1) ascend- 

 ing, to the orljit; (2) internal, to the mucous membrane of the nose; (8) de- 

 scending, to the liard and soft palate; and (4) posterior, to tlie ]>harvnx. 



(Ij Ascending branches. — The ascending or orbital branches are two or 

 three small twigs which enter the orbit through tlie spheno-maxillary fissure, and 

 proceed within the periosteum to the inner wall of the orbit, where they pass through 

 the posterior internal orbital canal and through the foramina in the suture behind 

 that canal to be distributed to the mucous membrane Avhich lines the posterior 

 ethmoidal cells and the sphenoidal sinus. 



(2) Iriternal branches. — The internal branches are derived in ])art from the 

 inner side of the ganglion, but are also largely made uj) of fibres which jiass from 

 tlie s])heno-palatine nerves without traversing tlie ganglionic substance. They are 

 dis])osed in two sets, the sujierior nasal and the septal. 



The superior nasal are six or seven small twigs which pass through the si)heno- 

 palatine foramen, and are distributed to the mucous membrane covering the; 

 j)osterior parts of the superior and middle turbinated bones. They also furnish 

 twigs to the lining membrane of the posterior ethmoidal cells. 



The septal branches are two or three in number, and ]>ass inwards through 

 the spheno-palatine foramen. They cross the roof of the nasal fossa to reach the 

 l)ack part of the nasal septum, where the smaller twigs terminate. The largest 

 nerve of the set, naso-palatine nerve, or nerve of Cotunnius, runs flownwards 

 and forwards in a groove in the vomer between the periosteinn and the mucous 

 membrane to the anterior ])alatine canal. Here it communicates with the nasal 

 branch of the anterior superior dental nerve. The two naso-palatine nerves then 

 pass through the foramina of Scarjta in the inti'rmaxillary suture, the left nerve 



