2l8 ANATOMY OF THE DOMESTIC FOWL 



its course supplies the adjacent parts. It enters into the formation 

 of the choroid plexus of the lateral ventricle. 



The internal ophthalmic artery extends out of the cranial cavity, 

 through the optic foramen, into the orbital cavity. It passes 

 upward along the interorbital wall and suppHes the optic nerve, 

 the trigeminus nerve trunk, and the eye muscles, and dorsally 

 anastomoses near the olfactory nerve with the rete ethmoidale and 

 the external ophthalmic artery, and continues as the ethmoidal 

 artery. 



The ethmoidal artery supplies the supra-orbital gland and the 

 gland of Harder. It gives off twigs to the rete ophthalmicum and 

 other branches to the skin of the frontal region, where it anastomoses 

 with branches of the external facial artery. These branches in 

 the frontal region are rather large. Large branches are given off 

 to the comb. 



The arieria ethmoidalis externa originates in the nasal cavity from 

 a division of the ethmoidal artery. 



The external ethmoidal artery passes below the lacrimal bone, 

 extends forward, suppUes the walls of the nasal cavity, and finally 

 sends a branch anteriorly into the upper median portion of the jaw 

 bone, and other branches to the septum nasi and other parts of the 

 nasal cavity. 



There are frequent anastomoses between the ethmoidalis interna, 

 the facialis, and the spheno-maxiJlary artery. 



The internal ethmoidal artery supphes principally the posterior 

 turbinated bones and septum nasi. 



Branches of the External Carotid Artery 



Branches from the external carotid and the facial artery supply 

 the tongue and its muscles, the larynx, the lower jaw bone, the 

 gums, and the upper lateral facial region. 



The external carotid (Fig. 62, No. ^,8) gives off the following 

 branches: 



First, the hyoid arteiy (Fig. 72, No. 12) which supplies the inner 

 portion of the depressor mandibular aAd also the cornua of the 

 OS hyoideum, and extends to the tip of the tongue. 



Second, the superior laxyngeal artery (Fig. 72, No. 16) which 

 supplies the sterno-brachialis and give? off branches which extend 

 downward to the trachea and to the esophagus. The main artery 



