——fs ae 
BRANCHES OF THE INTERNAL CAROTID ARTERY. 771 
* 
(dq) The lachrymal artery (a. lacrimalis), arises from the ophthalmic on the outer side of 
the optic nerve. It runs forwards along the upper border of the external rectus to the upper and 
outer angle of the orbit, and in its course gives off branches to the lachrymal gland, muscular 
branches to the external and superior recti, palpebral branches to the upper eyelid and the upper 
and outer part of the forehead, temporal and malar branches, which accompany the temporal and 
malar branches of the temporo-malar nerve, to the face and the temporal fossa respectively ; 
anterior ciliary branches (aa. ciliares anteriores), which perforate the sclera behind the corneo- 
scleral junction and anastomose with the posterior ciliary arteries ; and a recurrent meningeal 
branch, which passes backwards through the outer part of the sphenoidal fissure to anastomose in 
the middle fossa of the skull with the middle meningeal artery. 
(e) Muscular.—These branches are usually arranged in two sets, outer and inner. The former 
supply the upper and outer, and the latter the lower and inner orbital muscles. ‘They anastomose 
with muscular branches from the lachrymal and the supra-orbital vessels, and they give off 
anterior ciliary branches. 
(f) The supra-orbital branch (a. supra-orbitalis) is given off as the ophthalmic artery crosses 
above the optic nerve. It passes round the inner borders of the superior rectus and levator 
palpebrze muscles, and runs forwards between the latter and the periosteum to the supra-orbital 
notch, accompanying the frontal and supra-orbital nerves. Passing through the notch it reaches 
the scalp, and, perforating the frontalis muscle, anastomoses with the superficial, temporal, and 
frontal arteries. 
(g) Ethmoidal branches, anterior (a. ethmoidalis anterior) and posterior (a. ethmoidalis 
posterior), arise from the ophthalmic as it runs forwards along the inner boundary of the orbital 
Ascending parietal artery Ascending frontal arteries 
Parieto-occipital 
artery 
: pera) | Inferior external 
Calcearine artery. i : are of le A A\\ es WY frontal artery 
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van 
Calearine artery 
XK 
Parieto-temporal artery Temporal branches of middle cerebral 
Fic. 558.—DIstRIBUTION OF CEREBRAL ARTERIES ON THE OUTER SURFACE OF THE CEREBRUM. 
Anterior cerebral artery is coloured green, the middle cerebral red, and the posterior cerebral orange. 
cavity. They pass inwards between the superior oblique and the internal rectus. The posterior, 
which is much the smaller of the two, traverses the posterior ethmoidal canal, and supplies 
the posterior ethmoidal cells and the posterior and upper part of the outer wall of the nasal cavity. 
The anterior ethmoidal artery passes through the anterior ethmoidal canal with the nasal nerve, 
enters the anterior fossa of the skull, and crosses the cribriform plate of the ethmoid to the 
nasal notch, through which it reaches the nasal cavity, where it descends with the nasal nerve in 
a groove on the back of the nasal bone, and finally passes between the upper lateral cartilage and 
the lower border of the nasal bone to the tip of the nose. It supplies branches to the membranes 
of the brain in the anterior cranial fossa as well as to the anterior ethmoidal cells, the frontal 
sinus, the anterior and upper part of the nasal mucous membrane, and the skin on the dorsum 
of the nose. 
(h) Palpebral branches (aa. palpebrales), upper and lower, are given off near the termination 
of the ophthalmic. They are distributed to the upper and lower eyelids, and they anastomose with 
the lachrymal, supra-orbital, and infra-orbital arteries. 
(¢) The nasal terminal branch (a. dorsalis nasi) passes out of the orbit above the internal tarsal 
ligament. It pierces the palpebral fascia, and terminates on the side of the nose by anastomosing 
with the angular branch of the facial artery. 
(k) The frontal terminal branch (a. frontalis) pierces the palpebral fascia at the upper and 
inner part of the orbit, and ascends, with the supra-trochlear nerve, in the superficial fascia of 
the anterior and mesial part of the scalp, anastomosing with its fellow of the opposite side and 
with the supra-orbital artery. 
(6) The posterior communicating artery (a. communicans posterior) rises from the 
internal carotid near its termination. It runs backwards below the optic tract and in 
