THE AORTA OF THE RABBIT 
309 
A., 
C., 
i 
H, 
N., 
M., 
S. , 
T. , 
V„ 
X., 
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2. 
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EXPLANATION OF PRATE VHI 
Abbreviations ' 
Aorta, with its ascending transverse arch and descending (dorsal) 
portions. 
common carotid arteries, (R) right and (E) left. 
superior intercostal artery. 
heart 
innominate artery, 
internal mammary artery, 
subclavian artery, right and left. 
transverse scapular artery, including the superficial cervical artery, 
vertebral artery, right and left, 
axillary artery, right and left. 
Diagrammatic ventral view of the arteries of the thoracic regions ol 
the rabbit, showing the various branches as they occur in the major- 
ity of specimens." The innominate (brachio-cephalic) (N) and the 
left subclavian (S) are the two usual branches of the arch of the 
aorta. The left subclavian gives origin to a number of arteries as 
here shown, while the innominate bifurcates to form the two common 
carotids and thq right subclavian arteries. 
Schematic ventral view of the arteries of rabbit 32 which conspicu- 
ously indicates the vertebral artery of the right side as a branch of 
the right carotid artery. Notice on the left side the transverse 
scapular and the vertebral arteries are morphologically interposed 
and the intercostal and mammary arteries are separated by quite 
an interval. The left common carotid is well down; at the base 
of the innominate almost constituting a separate branch of the arch 
of the aorta. 
Ventral view of the arteries in rabbit 40. The vertebral artery of 
the left side is here formed close to the junction of the subclavian 
with the aortic arch, and thus forms what may be considered a 
third branch of the arch. The intercostal and mammary arteries of 
the left side are separated by a wide interval. 
Rabbit 53 shows the formation of common stalks (innominates) for 
the intercostal and mammary arteries of both sides as well as the 
transverse and superficial cervical of the right. The brachiocephalic 
gives rise immediately to the left common carotid. 
The arteries of rabbit 22 show differences in branches of the right 
and left subclavian vessels especially. The intercostal and mammary 
arteries originate separately on the right, the vertebral on the left 
is well cephalad of tne other vessels, and mjakes a bend caudo- 
mesad as here shown. Accessory vessels are found on the left side 
also. 
In rabbit 28 the formation of what may be termed a long corona 
of the left subclavian with a migration of the intercostal from the 
lateral surface of the subclavian to form a common stalk with the 
vertebral artery. The left common carotid artery is here a branch 
of the aortic arch so that three distinct branches are formed. The 
innominate is conspicuously long. 
Specinien 19 shows amon^ other variations the formation of the 
thyreoid ima, a small vessel originating on the innominate just 
caudad to the point of origin of the left commlon carotid artery and 
passing forward to the thyreoid gland of the neck. 
Rabbit 21 shows interesting relationships of the innominate, left 
comnion carotid and left subclavian arteries, and shows the com- 
paratively immediate subdivisions of the subclavian of either side. 
Such a condition may be designated as the short corona type. 
Specimen 106 shows the so-called thyreoid ima and other minor 
variations especially in the interval between the intercostal and 
mammary arteries of the right side, and the formation of the short 
corona type of the left subclavian artery. 
