W. p. GEIS AND M. P. KAYE 
305 
LT. STELLATE 
GANGLION 
RECURRENT 
CARDIAC 
RT. STELLATE 
GANGLION 
Figure 7. — Regional Denervation of the Canine Heart. 
Rt. Lateral View of Heart 
sympathetic innervation of sinus node 
fore, enter the heart subjacent to the adventitia 
of the great vessels. 
DISCUSSION 
Sites of Entry of Neural Elements 
Mizeres has anatomically described the only 
autonomic nerve which is large enough to trace 
to the heart : the VLCN.'^ This nerve reaches the 
pericardium as it descends anterior to the left 
pulmonary artery and left superior pulmonary 
vein. As it penetrates the pericardium, it 
branches profusely over the left wall of the left 
atrium. Randall has physiologically deter- 
mined the VLCN to be purely sympathetic and 
that it innervates the left atrium and the lateral 
and posterior walls of the left ventricle.^ Kaye 
has reported the other major sympathetic site 
of neural entry to both ventricles to be sub- 
jacent to the adventitia of the aorta and pul- 
monary arteries.^ These nerve pathways inner- 
vate the anterior walls of both ventricles and 
travel from base to apex." These investigators 
have recently demonstrated that the nerves 
entering along the great vessels also innervate 
the upper portion of the interventricular sep- 
tum.^ Moreover, they have delineated a third 
site of entry of sympathetic nerves to the ven- 
tricles. A group of nerves descend posterior to 
the heart and enter the heart in the oblique 
sinus at the junction of the inferior vena cava 
with the left atrium. These nerves provide sym- 
pathetic innervation to the posterior walls of 
both ventricles and to the interventricular sep- 
tum as well as parasympathetic and sympa- 
