Transcript Thorax: CT, axial sections

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 linedrawings 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 3rd edition
Second page number in parenthesis is Netter’s 4th edition
Introduction to the Thorax
Thorax drawings
Can you draw (or visualize) these anatomical structures:
An exercise in thoracic cross sectional anatomy recognition
See plate 208 (212)
See plate 233 (237)
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
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?
See plate 234 (238)
In addition to plate 208, this
drawing from Netter’s Atlas,
(dropped from the 3rd edition)
is helpful for following
pulmonary circulation.
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Image 9
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Superior vena cava
Arch of the aorta
Trachea
Esophagus
Body of the Rt scapula
Spinal cord
Body of the sternum
Presentation of Thorax Images
Reference
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.
Reference
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Superior vena cava
Brachiocephalic artery (233) (237)
Lt common carotid artery *
Rt pectoralis major muscle
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
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Images 8 & 7
* 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.
Images 8-5
Reference
Image #6 is very similar to 7. There is
nothing new to identify.
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Rt brachiocephalic vein
Lt brachiocephalic vein
Brachiocephalic artery
Lt common carotid artery*
Lt subclavian artery
Spine of the Rt scapula (scapular spine)
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* Because the Lt common carotid is against
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the Lt brachiocephalic vein the two blend
together.
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Images 6 & 5
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Reference
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Images 4 & 3
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Rt brachiocephalic vein
Lt brachiocephalic vein
Brachiocephalic artery
Lt common carotid artery
Lt subclavian artery
Rt sternoclavicular articulation (joint)
Rt lamina of a thoracic vertebra (16) (17)
Rt. pedicle of a thoracic vertebra
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Rt. subclavian artery
Rt common carotid artery
Lt axillary vein*
Lt subclavian vein
Lt. internal jugular vein**
Rt subclavian vein
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 4-1
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Reference
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Rt subclavian artery* (410, 412)(427 ,429)
Rt subclavian vein**
Rt internal jugular vein
Rt common carotid artery
Lt common carotid artery
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
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* 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.
Images 2 & 1
Reference
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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
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Images 10 & 11
Superior vena cava
Arch of Azygos vein* (226, 234)(230, 238)
Azygos vein
Hemiazygos vein
Trachea
Esophagus
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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.
Images 10-13
Reference
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Superior vena cava
Ascending aorta
Descending aorta
Lt pulmonary artery*
Carina of the trachea (198, 199) (202,203)
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6. Rt main bronchus (main stem)
7. Rt superior lobar bronchus
8. Tertiary (3rd level or segmental) bronchi
9. Lt pulmonary artery
10. Rt pulmonary artery** (202) (206)
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Images 12 & 13
Reference
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Superior vena cava
Ascending aorta
Rt pulmonary artery
Pulmonary trunk*
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.
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Images 14 & 15
Images 14-17
Reference
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Auricle of Rt atrium (208) (212)
Rt pulmonary artery*
Lt atrium
Pulmonary trunk
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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***
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* 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.
Images 16 & 17
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Another Look
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3D image of the thorax. Can you identify
the pulmonary vessels. Click for the legend.
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Rt pulmonary artery
Lt pulmonary artery
Pulmonary trunk
Ascending aorta
Rt pulmonary vein
Lt pulmonary vein
Thoracic aorta
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Another Look: 3D Thorax
Reference
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Rt atrium
Rt ventricle
Lt atrium
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.
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Images 18 & 19
Images 18-21
Reference
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Rt atrium
Lt atrium
Rt ventricle
Lt ventricle
Rt atrioventricular septum
Lt atrioventricular septum
Interatrial septum
Interventricular septum
On image 21 the atria are receded, as
the ventricles dominate.
Images 20 & 21
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Reference
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Rt ventricle
Lt ventricle
Interventricular septum
Inferior vena cava (216) (220)
Coronary sinus (210, 216) (214, 220)
Esophagus
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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.
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Pulmonary vasculature
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1 cm cut
thickness
{
Dome of diaphragm
Images 22 & 23
Image
s 2225
Reference
1. Rt ventricle
2. Lt ventricle
3. Posterior interventricular branch of the
Rt coronary artery (Posterior descending
artery) (212) (216)
4. Spleen
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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.
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Images 24 & 25
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Superior vena cava
Ascending aorta
Rt pulmonary artery
Descending aorta
Lt pulmonary artery
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Another Look: Double Window
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.