1. 25 Transaxial CT Images of the Thorax These images have been windowed to accentuate the water density structures of the heart and great vessels. As a result the lungs appear black, with little detail in them. Only the larger pulmonary vessels appear, as white spots around the hilar areas. On campus students must draw and identify the anatomy on the line- drawings on the next slide. Students in the degree completion course should have an understanding of vascular anatomy that make testing on the drawings unnecessary. But if you need a refresher try these drawings. The ability to visualize these structures is important to the study of cross sectional anatomy of the thorax. First page number in parenthesis is Netter’s 3 rd edition Second page number in parenthesis is Netter’s 4 th edition Introduction to the Thorax

2. 1 Superior & inferior vena cava 2 Rt. atrium 3 Tricuspid valve 4 Rt. ventricle 5 Pulmonic valve 6 Pulmonary trunk 7 Pulmonary arteries 8 Pulmonary circulation 9 Pulmonary veins 10 Left atrium 11 Mitral valve 12 Left ventricle 13 Aortic valve 14 Ascending aorta Can you draw (or visualize) these anatomical structures: An exercise in thoracic cross sectional anatomy recognition See plate 233 (237) See plate 234 (238) See plate 208 (212) Drawing the heart & pulmonary vessels is more of a challenge. If you can’t draw it can you visualize the trip blood makes from the vena cava to the aorta? In addition to plate 208, this drawing from Netter’s Atlas, (dropped from the 3 rd edition) is helpful for following pulmonary circulation. Thorax drawings

3. 1. Superior vena cava 2. Arch of the aorta 3. Trachea 4. Esophagus 5. Body of the Rt scapula 6. Spinal cord 7. Body of the sternum 4 5 6 7 3 21 Reference Presentation of Thorax Images When viewing images from superior to inferior the arteries and veins to the head and upper extremities are numerous, and can be difficult for students to identify. However, beginning at the level of the arch of the aorta, the origin of these vessels (Brachiocephalic, Rt common carotid, Rt subclavian, and the Superior vena cava) are easier to identify as they follow the course studied in a traditional anatomy course. For this reason the thorax will be studied in two parts: first everything above the heart, then the heart. The first image is 9, and progresses superior to 1. Then back to image 10 and on to 25. Images will be tested in this order. Image 9

4. 1. Superior vena cava 2. Brachiocephalic artery (233) (237) 3. Lt common carotid artery * 4. Rt pectoralis major muscle 5. Rt pectoralis minor muscle 6. Manubrium of the sternum 7. Rt brachiocephalic vein (234) (238) 8. Lt brachiocephalic vein ** 9. Lt costovertebral articulation (joint) 10. Rt costotransverse articulation * Unlike the illustration in Netter’s Atlas, the Lt. subclavian artery on this patient is considerably higher on the arch of the aorta than the Rt common carotid. The Lt subclavian will not appear until image #5. **Notice the shape of the superior vena cava in image #8. It is not a circle like in image 9 because, as is evident from image 7, it is at the anastomosis of the Rt and Lt brachiocephalic veins. 4 5 6 7 8 9 3 2 1 10 Reference Images 8 & 7

5. Images 8-5

6. Image #6 is very similar to 7. There is nothing new to identify. 1. Rt brachiocephalic vein 2. Lt brachiocephalic vein 3. Brachiocephalic artery 4. Lt common carotid artery* 5. Lt subclavian artery 6. Spine of the Rt scapula (scapular spine) * Because the Lt common carotid is against the Lt brachiocephalic vein the two blend together. Reference 4 5 6 3 2 1 Images 6 & 5

7. 4 5 6 7 8 9 3 2 1 10 11 12 13 14 Reference 1. Rt brachiocephalic vein 2. Lt brachiocephalic vein 3. Brachiocephalic artery 4. Lt common carotid artery 5. Lt subclavian artery 6. Rt sternoclavicular articulation (joint) 7. Rt lamina of a thoracic vertebra (16) (17) 8. Rt. pedicle of a thoracic vertebra 9. Rt. subclavian artery 10. Rt common carotid artery 11. Lt axillary vein* 12. Lt subclavian vein 13. Lt. internal jugular vein** 14. Rt subclavian vein 15. Sternal end of Rt. clavicle * The left axillary and subclavian veins are showing iodine contrast which is being drip infused into the left median cubital vein. The arms are above the patient’s head. ** At the anastomosis of the internal jugular and subclavian veins. Note the ring of contrast created by the non-iodinated blood from the head dumping iodine contrast into the subclavian vein. Images 4 & 3 15

8. Images 4-1

9. 1. Rt subclavian artery* (410, 412)(427,429) 2. Rt subclavian vein** 3. Rt internal jugular vein 4. Rt common carotid artery 5. Lt common carotid artery 6. Lt subclavian artery*** 7. Shaft of the Lt clavicle 8. Lt axillary vein with iodine contrast 9. Rt & Lt common carotid arteries 10. Rt & Lt internal jugular veins 11. Apex of Rt lung (plural = apices) 12. Acromion process of Lt scapula 13. Trachea 14. Esophagus * The circular part of the Rt subclavian artery (in the mediastinum) has been seen in previous sections. Now we see the lateral part of the artery after it crossed the apex of the lung and dropped back into view on this section, as it heads toward the axillary artery. ** Compare the relationship of the subclavian artery and vein to plate 412 (429). The arrow (#2) points to the area where a subclavian (central venous) catheter is punctured. *** Unlike the Rt side, the lateral portion of the Lt subclavian does not come into view in this study. Reference 4 5 6 7 8 9 32 1 11 13 14 10 12 Images 2 & 1

10. 1. Superior vena cava 2. Arch of Azygos vein* (226, 234)(230, 238) 3. Azygos vein 4. Hemiazygos vein 5. Trachea 6. Esophagus 7. Parietal pleura (228)(232) 8. Visceral pleura** (192-194)(196-198) 9. Rt intervertebral foramen 10. Ascending aorta 11. Descending aorta 12. Pulmonary vessels*** * Where the azygos turns anteriorly and joins the SVC. The circular structure in the middle area of this arch is probably an enlarged lymph node. See plate 235 (239). ** The pleural lining are not seen on this study, and are not normally identifiable unless there is pleural thickening or an effusion. But we know they are there. *** Arteries and veins above the hilum of the left lung. 4 5 6 7 8 9 3 2 1 10 11 12 Reference Images 10 & 11

11. Images 10-13

12. 1. Superior vena cava 2. Ascending aorta 3. Descending aorta 4. Lt pulmonary artery* 5. Carina of the trachea (198, 199) (202,203) 6. Rt main bronchus (main stem) 7. Rt superior lobar bronchus 8. Tertiary (3 rd level or segmental) bronchi 9. Lt pulmonary artery 10. Rt pulmonary artery** (202) (206) Reference 4 5 6 7 8 9 3 2 1 10 * ** Images 12 & 13

13. 1. Superior vena cava 2. Ascending aorta 3. Rt pulmonary artery 4. Pulmonary trunk* 5. Lt pulmonary artery 6. Azygos vein 7. Pulmonary trunk 8. Esophagus * At this level the right pulmonary artery is just arising from the pulmonary trunk. In image 15 (#7) the trunk is clearly seen, differentiated from the artery. 4 5 6 7 8 3 2 1 5 Reference Images 14 & 15

14. Images 14-17

15. 1. Auricle of Rt atrium (208) (212) 2. Rt pulmonary artery* 3. Lt atrium 4. Pulmonary trunk 5. Aortic sinus (root of the aorta)** (219) (223) 6. Lt coronary artery (212, 215) (226-219) 7. Lt (superior & inferior pulmonary) pulmonary veins (210-213) (214-217) 8. Thoracic aorta*** * At this level we see the last remnant of the Rt pulmonary artery. Notice that the emerging Lt atrium (#3) looks similar to the Rt pulmonary artery in image 15, but is in a different position. ** The Rt coronary artery (#5) identifies this as the area of the cusps of the valves known as the aortic sinus or root of the aorta. (219)(223) ***At the level of the aortic sinus the descending aorta becomes the thoracic or descending thoracic artery. Reference 4 5 6 7 8 3 2 1 3 1 Images 16 & 17

16. Another Look 3D image of the thorax. Can you identify the pulmonary vessels. Click for the legend. 4 5 6 7 3 2 1 1. Rt pulmonary artery 2. Lt pulmonary artery 3. Pulmonary trunk 4. Ascending aorta 5. Rt pulmonary vein 6. Lt pulmonary vein 7. Thoracic aorta 1 2 4 Another Look: 3D Thorax

17. 1. Rt atrium 2. Rt ventricle 3. Lt atrium 4. Lt ventricle The divisions between the chambers of the heart become a bit vague, especially on image 19, but there is no doubt where they are. A good mental exercise is to identify the structures on previous images that gave rise to each of the chambers, then look back on those images to appreciate why the chambers are where they are. 4 3 2 1 Reference 4 3 2 1 Images 18 & 19

18. Images 18-21

19. 1. Rt atrium 2. Lt atrium 3. Rt ventricle 4. Lt ventricle 5. Rt atrioventricular septum 6. Lt atrioventricular septum 7. Interatrial septum 8. Interventricular septum On image 21 the atria are receded, as the ventricles dominate. Reference 4 5 6 7 8 3 2 1 Images 20 & 21

20. 1. Rt ventricle 2. Lt ventricle 3. Interventricular septum 4. Inferior vena cava (216) (220) 5. Coronary sinus (210, 216) (214, 220) 6. Esophagus 7. Liver 8. Dome of the Lt hemidiaphragm* 9. Pericardial sac (pericardium) (211, 214, 215) (215, 218, 219) * The hazy appearance of the dome and the pulmonary vasculature in the base of the Lt. lung are seen together due to the partial volume effect. This is a good demonstration of two separate structures imaged in a one cm cut thickness. 4 5 6 7 8 9 3 2 1 4 6 Reference { 1 cm cut thickness Dome of diaphragm Pulmonary vasculature Images 22 & 23

21. Image s 22- 25

22. 1. Rt ventricle 2. Lt ventricle 3. Posterior interventricular branch of the Rt coronary artery (Posterior descending artery) (212) (216) 4. Spleen 5. Stomach 6. Intrahepatic inferior vena cava 7. Abdominal aorta The lung tissue in image 25, deep in the posterior costophrenic recess, has been windowed to best demonstrate lesions therein, which is why the water density organs of the abdomen appear different than they did at this level in the Abdomen unit. Reference 4 5 6 7 3 2 1 Images 24 & 25

23. Another Look This double windowed image of the thorax utilizes a cut and paste type of function to combine a lung window and water density window in a single image. The disadvantage is a loss of spatial resolution at the edges of the lung fields. Can you identify the mediastinal structures? Click for the legend. 4 5 3 2 1 1. Superior vena cava 2. Ascending aorta 3. Rt pulmonary artery 4. Descending aorta 5. Lt pulmonary artery Another Look: Double Window