BRANCHES OF THE OPHTHALMIC ARTERY 



553 



between the epicranius and the pericranium. Both branches anastomose with the anterior 

 branches of the superficial temporal, the angular branch of the external maxillary (facial), 

 and the transverse facial artery. The branches of the supraorbital are: — (a) periosteal, to 

 the periosteum of the roof of the orbit; (6) muscular, to the levator palpebral and superior rectus; 



(c) diploic, given off as the artery is passing through the supraorbital notch and, entering a 

 minute foramen at the bottom of the notch, is distributed to the diploe and frontal sinuses; 



(d) trochlear, to the pulley of the superior obUque; (e) palpebral, to the upper ej-ehd. 



(3) The arteria centralis retinae, a small but constant branch, comes off from the oph- 

 thalmic close to the optic foramen, and, perforating the optic nerve about 6 mm. (j in.) behind 

 the globe, runs forward in (the substance of the nerve) to the ej'ebaU, supplying the retina. 

 Its further description is given in the section on the Eye. 



(4) The muscular branches [rami musculares] are very variable in their origin and distri- 

 bution. They may be roughly divided into superior and inferior sets. The superior or smaller 

 set supply the superior oblique, the levator palpebrse, and superior rectus. The inferior pass 

 forward, between the optic nerve and the inferior rectus, supplying that muscle, the medial 

 rectus, and the inferior oblique. From the muscular branches are given off the anterior ciliary 

 arteries. (See Ciliary Arteries.) 



(5) The ciliary arteries are divided into three sets: — The short posterior, the long posterior, 

 and the anterior, (i) The short posterior [aa. cihares posteriores breves], five or six in number, 

 come off chiefly from the ophthalmic as it is crossing the optic nerve. They run forward about 



Fig. 455. — The Left Ophthalmic Artery and Vein. 



Supraorbital artery 



Lacrimal gland 



Superior rectus, cut 



Eyeball 



Lateral rectus 

 Lacrimal artery 



Superior rectus, cut 

 Inferior ophthalmic vem 

 Superior ophthalmic vein 



Optic nerve 



Superior ophthalmic vein 



Commencement of superior 

 ophthalmic vein 



Reflected tendon of superior oblique 

 Ophthalmic artery 



Anterior ethmoidal artery 



Posterior ethmoidal artery 

 Ciliary arteries 



Levator palpebra, cut 

 Annulus communis lof Zinn) 

 Ophthalmic artery 



Optic commissure 



Internal carotid artery 



the nerve, dividing into twelve or fifteen small vessels, which perforate the sclerotic around 

 the entrance of the optic nerve, and are distributed to the chorioid coat, (ii) The long posterior 

 ciliarj^ arteries [aa. ciliares posteriores long£e], usually two, sometimes three, in number, come off 

 from the ophthalmic on either side of the optic nerve, and run forward with the short cihary to 

 the sclerotic. On piercing the sclerotic, they course forward, one on either side of the eyeball 

 between the sclerotic and the chorioid to the ciliary processes and iris. Their further distribu- 

 tion is given under the anatomy of the Eye. (iii) The anterior ciliary arteries [aa. ciliares an- 

 teriores] are derived fi-om the muscular branches and from the lacrimal. They run to the globe 

 along the tendons of the recti, forming a zone of radiating vessels beneath the conjunctiva. 

 Some of them, the episcleral arteries [aa. episclerales]; perforate the sclerotic about 6 mm. 

 (j in.) behind the cornea, and supply the iris and ciliary processes. It is these vessels that are 

 enlarged and congested in iritis, forming the circumcorneal zone of redness so characteristic of 

 that disease. They then differ from the tortuous vessels of the conjunctiva in that they are 

 straight and parallel. The remainder constitute the anterior conjunctival arteries [aa. con- 

 junctivales anteriores]. 



(6) The posterior ethmoidal artery [a. ethmoidaUs posterior] (fig. 455) runs medially be- 

 tween the superior oblique and medial rectus, and, leaving the orbit by the posterior ethmoidal 

 canal, together with the posterior ethmoidal branch of the naso-ciliary (nasal) nerve, enters 

 the posterior ethmoidal cells, whence it passes through a transverse slit-hke aperture between 

 the sphenoid bone and cribriform plate of the ethmoid bone into the cranium. It gives off (a) 

 ethmoidal branches to the posterior ethmoidal cells; (6) meningeal branches to the dura mater 

 Uning the cribriform plate; and (c) nasal branches, which pass through the cribriform plate to 



