THORACIC CAVITY 129 



left border of the trachea and the oesophagus, and posterior to 

 the left common carotid artery. As it turns round the arch 

 it gives branches to the deep cardiac plexus, and, as it ascends 

 along the left border of the trachea, it gives offsets to the 

 trachea and to the oesophagus. 



The Deep Cardiac Plexus. The deep cardiac plexus lies 

 between the arch of the aorta and the bifurcation of the 

 trachea. It is more or less distinctly separable into right and 

 left parts, and the right part is connected with the superficial 

 cardiac plexus. The right part of the plexus receives (i) 

 three cardiac branches from the cervical part of the right 

 sympathetic trunk ; (2) the two cervical cardiac branches of 

 the right vagus ; (3) the cardiac branch of the right recurrent 

 nerve ; (4) the thoracic cardiac branch of the right vagus. 

 It is connected with the superficial cardiac plexus, and it gives 

 branches to (i) the right anterior pulmonary plexus; (2) 

 the right atrium ; (3) the right coronary plexus. The left 

 part of the deep cardiac plexus receives (i) the middle and 

 lower cervical cardiac branches of the left sympathetic trunk ; 

 (2) the upper cervical cardiac branch of the left vagus; (3) 

 the cardiac branches of the left recurrent nerve. It gives 

 branches to (i) the left anterior pulmonary plexus; (2) the 

 left atrium ; (3) the left coronary plexus. 



Dissection. Cut through the right and left bronchi, close 

 to their origins from the trachea ; then divide the trachea at 

 the upper aperture of the thorax and remove its thoracic portion, 

 but avoid injury to the vagi and the left recurrent nerves. The 

 extra-pulmonary parts of the bronchi will be retained in position 

 by the bronchial arteries and the branches of the pulmonary 

 plexuses ; and the thoracic part of the oesophagus will be fully 

 exposed. 



The Thoracic Part of the (Esophagus. The thoracic part 

 of the oesophagus enters the thorax at the upper aperture, 

 passes downwards, through the superior and posterior 

 mediastina, and leaves, at the level of the tenth thoracic 

 vertebra, by passing through the cesophageal orifice of the 

 diaphragm into the epigastric region of the abdomen. As it 

 enters the superior mediastinum it lies somewhat to the left 

 of the median plane, but as it descends it passes medially, 

 gains the median plane at the level of the fifth thoracic 

 vertebra, and continues downwards in that plane to the level 

 of the seventh thoracic vertebra. There it passes forwards 



VOL. II 9 



