1240 HUMAN ANATOMY. 



7. The inferior palpebral branches (rr. palpebrales inferiores) (Fig. 1060) 

 usually two in number, are the smallest of the terminal branches. They pass upward 

 from the infraorbital foramen, pierce the origin of the levator labii superioris, pass 

 around the lower margin of the orbicularis palpebrarum and supply the conjunctiva 

 and skin of the lower eyelid. 



8. The lateral nasal branches (rr. nasales externi) (Fig. 1060), from two to 

 four in number, pass inward under the levator labii superioris alaeque nasi and supply 

 the skin of the side of the nose. 



9. The superior labial branches (rr. labiales superiores) (Fig. 1060), two to 

 four in number, are the largest of the terminal branches. They pass downward 

 under the levator labii superioris and, after supplying the anterior portion of the 

 skin of the cheek, terminate in the mucous membrane and skin of the upper lip. 



The last three branches inosculate freely under the levator labii superioris with 

 the infraorbital branch of the facial, forming the infraorbital plexus (Fig. 1068). 



The Spheno-Palatine Ganglion. The spheno-palatine ganglion (g. spheno- 

 palatinum), also known as Meckel's, the spheno-maxillary or the nasal ganglion, is a 

 small triangular reddish-gray body, with the apex directed posteriorly, situated in 

 the upper portion of the spheno-maxillary fossa. It is flat on its mesial surface, 

 and convex on its lateral, and measures about 5 mm. in length. It lies in close 

 proximity to the spheno-palatine foramen and just beneath the maxillary branch of 

 the trigeminal nerve (Fig. 1061). The ganglion is regarded as belonging to the 

 series of sympathetic nodes, and consists of an interlacement of nerve-fibres in which 

 are embedded numerous stellate sympathetic neurones. 



Roots. The sensory root consists of two, sometimes three, short stout 

 filaments, the spheno-palatine nerves (nn. sphenopalatini), which pass directly 

 downward from the lower margin of the maxillary nerve to the upper border of the 

 ganglion. While some few of the fibres of this root are axones of the sympathetic 

 ganglion-cells, the great majority are dendrites of the cells of the Gasserian ganglion 

 which pass to a limited extent through, but mostly around, the spheno-palatine 

 ganglion independently of its cellular elements. They are continued entirely into the 

 various trunks that are usually described as branches of distribution of the ganglion 

 (see below). 



The motor root is the great superficial petrosal nerve (n. petrosus superficialis 

 major) which, in all probability, carries sensory as well as motor fibres. It arises from 

 the facial nerve in the facial canal, passes through the hiatus Fallopii and a groove in 

 the petrous portion of the temporal bone and then under the Gasserian ganglion to 

 reach the cartilage occupying the middle lacerated foramen. Here the great super- 

 ficial petrosal nerve is joined by the sympathetic root, the great deep petrosal, 

 (n. petrosus profundus), which is a branch from the carotid plexus. The two great 

 petrosal nerves fuse over the cartilage at the middle lacerated foramen to form the 

 Vidian nerve (n. canalis pterygoidei [Vidii] ) (Fig. 1061), which traverses the canal of 

 the same name and enters the spheno-maxillary fossa to join the spheno-palatine 

 ganglion. In its course through the canal the Vidian nerve gives off a few tiny 

 nasal branches, which, composed of trigeminal and sympathetic fibres, supply the 

 pharyngeal ostium of the Eustachian tube and the posterior part of the roof of 

 the nose and the nasal septum. While in the canal, the Vidian nerve receives a 

 filament from the otic ganglion. 



In addition to supplying (according to many anatomists) motor fibres to the levator palati 

 and a/ygos uvulae muscles, some of tin.- farial fibres are especially destined for glandular struc- 

 tures. Such fibres are probably interrupted around the stellate cells of the spheno-palatine 

 ganglion, the axones of which then complete the paths for the secretory impulses. The sensory 

 constituents of tin- great superficial petrosal nerve are, perhaps, of two kinds: (a) fibres from 

 the cells of the geniculatr ganglion of the facial to the palatine taste-buds, and (b} recurrent 

 trigeminal fibres, that, by way of the maxillary, spheno-palatine and great superficial petrosal 

 nerves, are distributed with the peripheral branches of the Vidian or of the facial nerve. 



The great deep petrosal nerve represents the association cord between the superior cervical 

 sympathetic and the spheno-palatine ganglion. Many of its fibres end in arborizations around 

 the stellate spheno-palatine cells, from which, in turn, axones pass to blood-vessels and glands 

 by way of the ganglionic branches of distribution. 



