MAMMALIA. i 89 



FIG. II. 



THE SYMPATHETIC NERVE IN THE LEFT SIDE 



OF THE CALF. 



(BOS TAURUS.) 



IN this figure the heart is placed for showing the left coronary artery. 



1. Prolongation of the sympathetic passing to the first thoracic ganglion ; about 



the middle of the neck a small ganglion appears to be inserted into it whilst 

 it is connected with the par vagum, and from this small ganglion a branch 

 accompanies an artery to the muscles on the outer part of the neck. 



2. First thoracic ganglion : many branches are given off from it, which form a 



plexus, and give filaments to the pulmonary artery and aorta and the right 

 auricle, and then accompany the right coronary artery to terminate on the 

 right ventricle of the heart ; the termination is seen in Fig. 1. 



3. Left thoracic plexus : it arises from the first, second, third, and fourth thoracic 



ganglia of the sympathetic ; it sends branches some way with the left azygos 

 vein to the left auricle and ventricle, and to communicate with branches from 

 the right thoracic plexus, coming from behind the inferior cava, and others 

 from behind the oesophagus. 



4. Trunk of the par vagum. 



5. Recurrent nerve. 



6. Phrenic nerve. 



7. Two large branches from the sixth cervical nerve communicate with a branch 



from the first thoracic ganglion of the sympathetic, and then pass to be 

 distributed to a muscle on the anterior part of the spine, and the others are 

 connected with the first thoracic ganglion of the sympathetic. 



