640 THE NERVOUS SYSTEM. 
In the cavity of the cranium the nerve gives off a minute recurrent branch (n. 
meningeus) to the dura mater of the middle fossa of the base of the skull. 
In the spheno-maaxillary fossa the nerve gives off—(1) two short thick spheno- 
palatine nerves (nn. spheno-palatini), the short or sensory roots of the spheno- 
palatine (Meckel’s) ganglion. (2) A posterior dental nerve, which may be double 
(nn. alveolares superiores), descends through the pterygo- -maxillary fissure to the 
outer side of the upper jaw, and proceeds forwards along the alveolar arch, in 
company with the posterior dental artery. It supplies the gum and the upper 
molar teeth by branches which perforate the bone to reach the alveoh. The nerve 
forms a fine plexus joined by the middle dental nerve before finally reaching the 
teeth. (5) A small orbital branch (n. zygomaticus) enters the orbital cavity through 
the spheno-maxil- 
lary fissure, and 
proceeding along 
the outer wall, it 
communicates with 
the lachrymal 
nerve, and passes 
through the orbital 
canal in the malar 
bone, where it 
divides into malar 
and temporal 
branches. The 
malar branch (n. 
zy gomatico-faci- 
alis) appears on the 
face, after travers- 
ing the malar 
bone, and supplies 
the skin over that 
bone. It com- 
municates with the 
malar branches of 
the facial nerve. 
The temporal 
Fic. 461.—ScHEME OF THE COURSE AND DISTRIBUTION OF THE SUPERIOR 
MAXILLARY NERVE. branch (n. ZY ZO- 
Rec, Recurrent branch in the middle fossa of the skull ; M.G, Meckel’s ganglion in matico-temporalis ) 
the spheno-maxillary fossa ; §.P, Spheno-palatine nerves ; 8.N, Superior nasal perto rates the 
branch ; Orb, Orbital nerve; T, Temporal, and M, Malar branches ; 1.0, zyoomati “ 
EE ee oe , ; atic = surfa 
Infra-orbital nerve, appearing on the face; P, Palpebral; N, Nasal, and YS . 0g 
; A.D, Anterior dental branch; M.D, Middle dental of the malar bone, 
branch ; N.P, Naso-palatine nerve ; P.D, Posterior dental branch; I.N, Inferior and 1s distributed, 
nasal branch ; L.P.P, Large posterior palatine nerve ; S.P.P, Small posterior after piercing the 
palatine nerve ; Acc, Accessory posterior palatine nerve; Vid, Vidian is) 
nerve ; Pt.Pal, Pterygo-palatine branch. temporal fascia, to 
the skin over the 
fore part of the temple. It communicates with the temporal branches of the 
facial nerve. It may be very minute, and not pass further than the temporal 
fascia, between the two layers of which it may form a communication with the 
facial nerve. (4) The infra-orbital nerve (n. infra-orbitalis) is the terminal branch 
of the superior maxillary nerve, which enters the orbit through the spheno- 
maxillary fissure and traverses the infra-orbital canal to reach the face. 
In the infra-orbital canal the superior maxillary, now called the infra-orbital 
nerve, supplies one and sometimes two branches to the teeth—the middle 
and anterior dental nerves (rr. alveolares superiores medius and anterior). 
The former may be only a secondary branch of the latter nerve, or they may 
arise independently from the infra-orbital nerve. However formed, the nerves 
descend in bony canals in the wall of the antrum of Highmore (to the lning of - 
which branches are given), and reach the alveolar arch, where they form minute 
plexuses and supply the teeth (joining posteriorly with the branches of the posterior 
L, Labial branches ; 
