30 ANATOMY. 



Describe the Inner Wall of the Orbit. Formed by the nasal process 

 of the superior maxillary bone, 20 the lachrymal, 6 the os planum of the ethmoid,' 2 

 and the body of the sphenoid, 3 it presents 



A Groove, for the lachrymal sac, and the Lachrymal Crest, anteriorly. 



2 Sutures, the ethmo-lachrymal, and the ethmo-sphenoidal. 



Describe the Outer Wall of the Orbit. Formed by the orbital pro- 

 cess of the malar bone, 9 and the greater wing of the sphenoid, 5 it presents the 

 Orifices^* of the malar canals, and the Spheno-malar Suture. 



Describe the Angles of the Orbit. They present the following points. 



IN THE SUPERIOR EXTERNAL ANGLE. 



Sphenoidal Fissure?** or foramen lacerum anterius, transmits the 3d, 4th, 

 ophthalmic division of the 5th, and the 6th nerves, the ophthalmic vein, 

 branches of the lachrymal and middle meningeal arteries, filaments of 

 the sympathetic nerve, and a process of the dura mater. 



Articulations, the fronto-malar, and fronto-sphenoidal. 



IN THE SUPERIOR INTERNAL ANGLE. 



Suture, the lachrymo-ethmo-frontal, in which are the following foramina. 

 Anterior Ethmoidal Foramen^ transmitting the anterior ethmoidal artery 



and the nasal nerve. 

 Posterior Ethmoidal Foramen?" 1 transmitting the posterior ethmoidal artery 



and vein. 

 IN THE INFERIOR EXTERNAL ANGLE. 



Spheno-maxillary Fissure (described under the Zygomatic Fossa). 

 IN THE INFERIOR INTERNAL ANGLE. 



A Suture, the ethmo-maxillo-palato-lachrymal. 



What other points are connected with the Orbit? Two, the supra- 

 rxbital notch, and the optic foramen, as follows, viz. 



Supraorbital Notch or Foramen at the junction of the inner and middle 

 thirds of the upper circumference, transmitting the supraorbital artery, 

 veins, and nerve. A line prolonged from this notch through the interval 

 between the bicuspid teeth of either jaw, will cross both the infraorbital 

 and mental foramina, and the canine fossa of the superior maxillary bone. 



Optic Foramen?- at the apex, is formed by the 2 roots of the lesser wing 

 of the sphenoid, and transmits the optic nerve and the ophthalmic artery. 

 From around its margin arises a tendinous ring, the common origin of the 

 4 recti muscles of the eye. 



What Muscles arise within the Orbit ? The 4 recti and 2 oblique of the 

 eye, the levator palpebrae, and the tensor tarsi (8 in all). 



