ANGEIOLOGY. 85 
far as the ciliary circle, where they subdivide; 6, muscular arteries to the 
different muscles in the orbit; 7, etimordal, to the mucous membrane in the 
ethmoidal cells; 8, superior and inferior palpebral to the palpebree, caruncula, 
conjunctiva, and lachrymal sac ; 9, nasal, to the side of the nose; 10, fron- 
tal, to the eyebrow and forehead. 
The posterior communicans arises from the carotid opposite to the 
ophthalmic, passes backwards and inwards, and joins the posterior cerebral 
circle. 
The antervor cerebri, or arteria callosa, passes forwards and inwards above 
the optic nerve, anastomosing with the opposite by a short transverse branch, 
the anterior communicans, and ultimately terminates by dividing into 
branches for the corresponding hemisphere of the cerebrum. 
The media cerebri, or middle cerebral artery, passes outwards in the fissure 
of Sylvius, and divides into two tortuous branches which supply the anterior 
and middle lobes of the cerebrum, sinking deep in the sulci between the 
conyolutions in the island of Reil. 
Pl. 135, fig. 5, distribution of the ophthalmic artery: *, superior dental; 
*, inferior dental; *, internal carotid; *, ophthalmic artery; °, muscular 
branches; ‘, lachrymal; ‘, supra-orbital; *, frontal artery; °, a short or 
posterior ciliary; ”, a long ciliary; '”"', ethmoidal; ”, frontal branch. 
Fig. 6, some of the deep branches of the ophthalmic, the eyeball removed : 
‘, ophthalmic; *, artery of the lachrymal sac; *, superior, and *, inferior 
palpebre. /%g. 7, cerebral arteries: *, anterior; *, middle lobe of the 
cerebrum; °, fissure of Sylvius; *,pons varoliu; °, cerebellum; °, medulla 
oblongata; ’, section of the trunk of the internal carotid; *, posterior com- 
municans; *, choroid artery; ", artery of the corpus callosum; ™, anterior 
communicans. 
C. The Subclavian Arteries and their continuations. 
The great arterial trunks, of which the subclavian constitute the initial 
portion, have different names in different parts of their course, the series 
consisting of the subclavian proper, the axillary, the brachial, and the radial 
and ulnar. | 
1. THE SUBCLAVIAN ARTERIES PROPER. The right and left subclavian 
arteries differ in diameter, length, situation, and relation. The right, as 
arising from the innominata, is shorter than the left, which springs from the 
arch of the aorta. The course of each may be divided into three stages : 
the first extends from the origin to the tracheal edge of the scalenus anti- 
cus; the middle stage is the transit of the artery between the scaleni mus- 
cles; the third stage extends from those muscles beneath the clavicle to the 
lower border of the first rib, below which the continued trunk receives the 
name of axillary artery. In the middle and last stages the right and left 
arteries are similarly circumstanced in all respects; the first stage is much 
longer on the left than on the right side. 
The right subclavian, in its first stage, passes outwards and a little 
upwards, having anterior to it the internal jugular and subclavian veins, 
the sterno-mastoid, hyoid, and thyroid muscles. The left subclavian, from 
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