E. Mediastinal pleura, forming a second investment for the heart, bloodvessels, &c. F. Costal pleura, seen to be continuous above with that which forms the mediastinum. G. Vena cava superior, entering pericardium to join V, the right auricle. H. Upper third of sternum. I I. First ribs. K K. Sternal ends of the clavicles. L. Upper end of sternum. M. Lower end of sternum. N N. Fifth ribs. O O. Collapsed lungs. P P. Arching diaphragm. Q. Subclavian artery. R. Common carotid artery, at its division into internal and external carotids. S S. Great pectoral muscles. T T. Lesser pectoral muscles. U. Mediastinal pleura of right side. V. Right auricle of the heart. [Illustration: Upper body, showing internal organs of neck and chest.] Plate 1 PLATE 2. A. Right ventricle of the heart. A a. Pericardium. B. Pulmonary artery. B b. Pericardium. C. Ascending aorta. C c. Transverse aorta. D. Right auricle. E. Ductus arteriosus in the loop of left vagus nerve, and close to phrenic nerve of left side. F. Superior vena cava. G. Brachio-cephalic vein of left side. H. Left common carotid artery. I. Left subclavian vein. K. Lower end of left internal jugular vein. L. Right internal jugular vein. M. Right subclavian vein. N. Innominate artery--brachio-cephalic. O. Left subclavian artery crossed by left vagus nerve. P. Right subclavian artery crossed by right vagus nerve, whose inferior laryngeal branch loops under the vessel. Q. Right common carotid artery R. Trachea. S. Thyroid body. T. Brachial plexus of nerves. U. Upper end of left internal jugular vein. V V. Clavicles cut across and displaced downwards. W W. The first ribs. X X. Fifth ribs cut across. Y Y. Right and left mammae. Z. Lower end of sternum. [Illustration: Upper body, showing internal organs of neck and chest.] Plate 2 COMMENTARY ON PLATES 3 & 4. THE SURGICAL FORM OF THE SUPERFICIAL CERVICAL AND FACIAL REGIONS, AND THE RELATIVE POSITION OF THE PRINCIPAL BLOOD-VESSELS, NERVES, &c.