TUK TIU<;I'.MI\\\L .v /;// 1 /: 



965 



The supra-orbital nerve, the largest of the three branches, leaves the orbit at 

 the supra-orbital notch (fig. 701). As it passes through the notch it gives off a small 

 branch which enters 1 he In me a nil supplies the diploe and I he mucous membrane ( if the 

 frontal sinus. Its terminal branches <ri\e twigs to the pericranium ami to the skin 

 of the BCalp, the Upper eyelid, t he frontal reirion. ami the parietal region almost as far 

 as the lambdoid suture (li;:. 7< ).">). ' die branch running at the upper margin of 1 he 

 orbital cavity unites with a branch of the- facial nerve. 



The frontal branch, given off at a variable point, lies internal to the supra- 

 orbital, passes through the frontal foramen, and is distributed to the skin of the fore- 

 head and upper eyelid (Cur. 701). 



The supratrochlear branch runs forwards and inwards towards the upper and 

 inner angle of the orbit, where it passes above the pulley of the superior oblique 

 muscle, pierces the palpebral fascia, and ascends to the lower anil middle part of 

 the forehead, accompanied by the frontal artery (fig. 701). Before it leaves the 



FIG. 701. NERVES OP THE ORBIT FROM ABOVE AND BEHIND. (Schematic.) 



i\ri:A-rnn< -iiu; \ n 

 , .vr/'/.M /'/.'/< ///,/. i/.' 



| , l-l:MM. A'/.MV// OF FRONTAL 

 SUPRAORBITAL 



. i .XT/?/? ion 



KTI/MnlliA/. 



Superior obliqur . 

 muscle 



Internal rectuw 



POSTERIOR 

 ETHMOIDAL 



TSOCOLSAB 



.Y.I /-</ /./JAM' 



. I /. , 

 AXxri. 1/1' I-DMHD v 



TKXIKIX "f //.V.V 



OPTIC i_ 



."is sin'tt , 



/ carotid 

 artery 

 A Bill 



SEXILVNAR 



( a. i xv /:/./. i. V) 

 OANOUOff 



Levator palpebrae 



uperiorie 

 , Superior rectua 



^LACHRYMAL HLAXII 



,.<//;;; I II.IART XKKTKS 



AX.I.TIIHO.I/XI; itlt.\\rn 

 ' 



.. LAI'illtYM.tr. 

 . l.'ISIl CILIA 



Inferior rectua 



BKAXI'H Til IXTP.IIXAL 



External rectus 



1SY.VI-ITIIKT1C 



mini:!- 

 LOXI1 



rool.o/ 



iary 



\ rool. 

 1 cilia 

 ) ganyli 



1XFKKHIR RKAXrHOF 



oceio-xoToa 



avpKiiinK .i.viv/ or 



i" ' I.li-MIJTOR 

 External rectua 



(lat. head) 

 OPHTHALMIC 

 MAXILLARY 



-JIA. \-lllBCLAR 



FORAMEN SPiNOSUM 



Dura mater 



orbit it sends a branch downwards behind or in front of the pulley of the obliquus 

 superior to communicate with the infratrochlear nerve, and as it leaves the orbit it 

 gives off filaments to supply the skin and conjunctiva of the inner third of the upper 

 eyelid. Its terminal branches pierce the orbicularis and frontalis, and, as they pass 

 to the skin of the forehead, they communicate with branches of the facial nerve. 



(h) The Lachrymal Nerve is the smallest of the three branches of the ophthalmic 

 division. It passes through the superior orbital (sphenoidal) fissure external to and 

 sligfitly below the frontal nerve, and is directed forwards and outwards, along the 

 upper border of the rectus lat era Us to the lachrymal eland (fig. 701). ( >n the lateral 

 wall of the orbit it receives a small communicating branch from the /ygomatic nerve 

 (the orbital branch of the maxillary nerve). This communicating branch brings to 

 the lachrymal nerve secretory fibres for the lachrymal gland. A small twig passes be- 

 yond the gland, pierces the palpebral fascia, supplies filaments to the conjunctiva, 

 and is then distributed to the integument at the outer canthus of the eye and to the 

 skin over the external angular process. 



