2l6 ANATOMY OF THE DOMESTIC FOWL 



The occipital artery originates either from the carotis communis 

 or sometimes from the superior cervical. 



BRANCHES OF THE CAROTIS CEREBRALIS 



The branches of the carotis cerebralis are as follows: 



1. The occipitalis (Fig. 72, No. 18), which in turn gives off, first, 

 the occipitalis sublimis. The occipitalis sublimis supplies the outer 

 and the middle portion of the digastricus and the posterior mylo- 

 hyoideus muscle. It also gives off, second, the occipitalis profunda 

 which supplies the inner portion of the digastricus muscle and 

 becomes the meningeal artery, which passes through the foramen 

 vagi, entering the brain cavity, where it supplies the coverings of 

 the brain as far as the sella turcica. Superficial branches of this 

 artery are distributed to the muscles in the region of the atlas and 

 anastomose with the vertebral artery. 



2 . The ophthalmica externa, which passes below the articulation 

 of the quadrate bone, around the tympanic cavity, enters the 

 canalis caroticus, and passes into the cranial cavity. The ramus 

 occipitalis, passing out of the same foramen, again enters the diploe 

 of the cranium; then after passing dorsally over the upper outer 

 semicircular canal of the ear, passes backward through the occipital 

 bone. 



The ophthalmica externa (Fig. 72, No. 9) forms a main trunk and 

 gives off two branches: the temporal artery and the recurrent 

 ophthalmic. The recurrent ophthalmic gives off the rete temporalis, 

 rete ethmoidalis, a branch to the orbital gland, and finally anastomo- 

 ses with its own branches and with those of the internal ophthalmic 

 at the olfactory foramen and aids in forming the ethmoidal artery. 

 These arteries supply blood by giving off branches to the muscles 

 of the eye, sclerotic coat, iris, choroid coat, and the ciliary bodies. 

 It gives off another branch to Harder's gland, and finally anastomo- 

 ses with the ethmoidalis. 



3. The plexus temporalis, rete mirabile ophthalmicum, or won- 

 derful network (Fig. 72, No. 8), is formed between the second and 

 the third trunk of the trigeminus nerve and the rete ophthalmicum. 



Inferior to this is the alveolar plexus, which plexus accompanies 

 the third branch of the trigeminus into the lower jaw. Two main 

 branches form this plexus, one coming from the carotis facialis,, 

 which anastomoses with the alveolar artery. 



