chest x-ray anatomy

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Living Anatomy of the Chest for 1st year Medical

Students

Original version compiled by Dr. Gillian Lieberman for the Harvard Medical School Human Body Lecture

Series. Adapted here for Independent Study.

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Living AnatomyRadiology is ideally suited to image anatomy in the living patient.

Labeled plain film Chest X-Rays (CXR), Angiograms, Bronchograms, Computed Tomography (CT) and Magnetic Resonance Images (MRI) follow, accompanied by anatomic diagrams to help familiarize you with chest anatomy.

Areas covered include:The Heart: Chambers, valves, great vessels, coronary arteriesThe Lungs: Lobes, pulmonary arteries, bronchial treeThe PleuraThe Azygos-Hemiazygos venous system

Basic Radiologic principles are outlined to facilitate plain film interpretation.

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Anatomy on Normal Chest

X-Ray

CXR-PA

Key:

1. Right 1st rib

2. Right 2nd rib

3. Scapula

4. Trachea

5. Carina

6. Bronchus seen end on

7. Bilateral hila

8. Branch of right main descending pulmonary artery

9. Right minor (horizontal fissure)

10. Right hemi diaphragm

11. Left hemi diaphragm

12. Gastric air bubble

13. Left clavicle

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Anatomy on Normal Chest

X-Ray

CXR-Left LAT

Key:

1a. Manubrium sternum

1b. Body of sternum



4a. Right scapula

4b. Left scapula

5. Trachea

6. Soft tissue of the arms

7. Major fissure

8. Minor fissure-little higher in this patient than the usual

9a. 9th left rib

9b. 9th right rib

T2-11 Thoracic vertebrae

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This film is helpful to demonstrate some basic radiologic principles which are essential to understanding x-ray interpretation.

Key:

1. Denser and smaller right upper lobe due to pneumonia

2. Elevated minor fissure

3. Top surface of liver

4. Undersurface of diaphragm

5. Top surface of diaphragm

6. Top surface of spleen

7. Free air in the abdominal cavity = pneumoperitoneum

Right Upper Lobe Pneumonia with Partial Volume Loss Pneumoperitoneum

Radiologic Principles: I

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The plain films are made up of four densities-

Black Air e.g. in lungs,stomach

Fat

Soft tissue which include muscle, organs e.g. liver, fluid e.g. blood

White Bone heavy metal e.g. calcium, iron

A line or border is seen only when there is an interface between two of these densities. E.g. The right heart outline is usually seen because soft tissue density of the heart is next to air density of the right middle lobe of the lung.

Air

Fat

Bone

Soft Tissue

Radiologic Principles: II

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Radiologic Principles: IIIPneumoperitoneum

Free air in the abdomen (always abnormal) (pneumoperitoneum) rises to a position under the diaphragm when the patient is upright. It therefore outlines the top of the liver on the right, the top of the spleen on the left, and undersurfaces on both hemi diaphragms. These are usually hot seen because liver, spleen and diaphragm are all soft tissue and therefore no interface is present. The upper border of the diaphragms are usually seen because air in the lower lung lobes abut the soft tissues of the diaphragm.Pneumonia

In pneumonia, the air in the lung gets replaced with fluid which shows up soft tissue density on x-ray. The lung lobe often also gets smaller or consolidated so the fissures move. Bacterial infection commonly respects the lobar boundaries as in this case.

Pneumonia

Pneumoperitoneum

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Lobes of the LungIMPORTANT FACTS:

The right lung has 3 lobes (separated by the major Oblique fissure & minor Horizontal fissure)

-Right upper lobe

-Right middle lobe

-Right lower lobe

The left lung has 2 lobes separated by major (oblique) fissure

-Left upper lobe

(medial portion is called the lingula)

-Left lower lobe

Lobes and Fissures of the Lung (from the front)

“Man’s Anatomy” by Tobias & Arnold

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The pleura is the lining of the lungs.

There are 2 layers -1. The visceral pleura hugs the lung lobes

-2. The parietal pleura hugs the chest wall

The pleural space is a potential space between the two.

A pneumothorax is the presence of air (always abnormal) in the pleural space.

A pleural effusion is the presence of detectable fluid (always abnormal) in the pleural space.

A hydropneumothorax is air and fluid in the pleural space.

Coronal Section of Pleural Sacs(schematic)

The Pleura

“Man’s Anatomy” by Tobias & Arnold

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Lobes of the Lung

This film is included because it helps demonstrate the 3 lobes of the right lung, the pleura and the pleural space.

Key:

1. Normal pointy left costophrenic angle

2. Blunted denser right costophrenic angle due to fluid in pleural space = pleural effusion

3. Air in pleural space = pneumothorax

4. … partially collapsed right upper lobe

5. ---partially collapsed right middle lobe

6. -.-partially collapsed right lower lobe

7. Visceral pleura of right middle lobe

8. (Position of parietal pleura – not seen)

9. Left breast shadow. (Notice the right breast has been removed = right mastectomy)Pneumothorax and pleural effusion = hydropneumothorax

Common causes for hydropneumothorax include rib fractures penetrating chest wounds e.g. stab or bullet wounds and iatrogenic causes e.g. lung biopsies or effusion drainages.

Right Tension Pneumothorax

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Anatomy on Normal Chest X-RayHeart borders and chambers of the heart on PA and lateral views.

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Heart Chambers and ValvesThe heart is made up of 4 chambers. The right side which handles deoxygenated blood is separated from the left side which handles oxygenated blood by septa, the top is separated from the bottom by valves.

Simplistic view: 1

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Venous Return to the HeartThe atria receives blood from the body and lungs.

The SVC and IVC bring deoxygenated (blue) blood to the right atrium from the body. The pulmonary veins bring oxygenated (red) blood to the left atrium from the lungs.

Simplistic view: 2

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Arterial Output from the HeartThe ventricles receive blood from their respective atria.

The right ventricle pumps deoxygenated blood via the pulmonary artery to the lungs.

The left ventricle pumps oxygenated blood via the aorta to the body.

The entrance to the aorta and the pulmonary artery have aortic and pulmonary valves respectively.

Simplistic view: 3

Pulmonary valve Aortic valve

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Heart ValvesThis patient had a malfunctioning mitral valve (between left atrium and left ventricle) and aortic valve (between left ventricle and aorta) and prosthetic valves were inserted (better seen on lateral)

Frontal CXR LAT CXR

Key:

1. Suture material used for repair of vertical incision thru sternum (median sternotomy)

2. Aortic valve prosthesis

3. Mitral valve prosthesis



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The pulmonary artery and aorta cross one another in the mediastinum.

Schema of great vessels connected to the heart

“Man’s Anatomy by Tobias & Arnold

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The Aortic arch


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Great Neck Vessels


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Angiograms-Aortic arch angiogramAn angiogram is an x-ray examination of blood vessels following contrast administration.

Arteriogram = Arterial Study

Venogram = Venous Study74

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Pulmonary Art #1Key:

1. Right main pulmonary artery branch

2. Right upper lobe pulmonary artery branch

3. Right middle lobe pulmonary artery branch

4. Right lower lobe pulmonary artery branch

5. Left main pulmonary artery

6. Left upper lobe pulmonary artery branch

7. Left lower lobe pulmonary artery branch

8. Pulmonary veins

9. Left atrium

10. Left ventricle

11. Ascending aorta

12. Descending aorta

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Angiograms-Pulmonary arteriogram (PA gram)

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8. Pulmonary veins

9. Left atrium

10. Left ventricle

11. Ascending aorta


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8. Pulmonary veins

9. Left atrium

10. Left ventricle

11. Ascending aorta


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Cardiomegaly plus early Congestive Heart Failure (CHF) Key:

1. Inferior vena cava (IVC)

2. Superior vena cava (SVC)

*3. Azygos vein

4. Carina

5. Trachea

6. Right main stem bronchus

7. Prominent pulmonary vessels

Heart and Vessels

Any and or all heart chambers may enlarge when the heart becomes diseased. Cardiomegaly = a big heart.

A patient’s heart enlarges due to a number of diseases e.g. valve disease, high blood pressure, congestive heart failure.

If the heart fails, the lung often become congested. Early on the pulmonary vessels appear more prominent as in this case. More advanced failure can result in a condition of pulmonary edema which is fluid flooding into the alveoli of the lungs causing the patient marked shortness of breath.

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Azygos-Hemiazygos venous system

The Azygos vein receives tributaries from intercostal veins as outlined. It is seen as an oval density to the right of the trachea just above the right main stem bronchus on all chest x-rays (*3 on the earlier film)

This is the portion that travels forward to join the SVC.

In CHF, the Azygos vein dilates and this density becomes prominent as seen on the previous patient’s CXR.


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Coronary arteries


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Coronary artery anatomy

LCX)


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Coronary Angiograms

LT Coronary Art LAO

Obtuse Marginal Artery

Left circumflex artery

Left main coronary artery

LAO

Diagonal artery

The coronary arteries can be outlined in the living patient by injecting contrast into them. A catheter (tube) is threaded through the Patients vessels to the heart, to gain access- called “cardiac catheterization”

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Coronary AngiogramsLT Coronary Art LAO

Left main coronary artery

LADDiagonal artery

Sinus Node Artery

AV Groove

Left circumflex artery

Obtuse marginal artery

Septal perforator

IV Groove

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Coronary AngiogramsRT Coronary Art LAO

Acute marginal artery

AV Node A

CruxPosterior LV Bronch

Conus Bronch

RCA

AV Groove

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Coronary AngiogramsRT Coronary Art RAO

Acute Marginal Arteries

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Bronchial segmental anatomy


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Normal BronchogramContrast agent can be instilled or inhaled into the bronchial tree outlining the walls of the trachea, main stem bronchi, segmental and even subsegmental bronchi

Frontal CXR Lateral CXR

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Bronchiectasis = localized irreversible dilatation of the bronchial tree

Contrast agent can be instilled or inhaled into the bronchial tree outlining the walls of the trachea, main stem bronchi, segmental and even subsegmental bronchi

Abnormal Bronchogram: Bronchiectasis

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Computed TomographyComputer tomography (CT) scanning obtains multiple cross sectional images through a patient using x-rays and computer enhancement. (Imagine slicing a sausage crosswise into many round equal thickness slices and then looking at these to see what’s in the sausage)

CT, ultrasound and magnetic resonance imaging (MRI) all allow imaging of the body in different planes.

TERMINOLOGY:

The following description considers the body in the anatomical position

Axial plane (=cross section) a plane of the body parallel to the horizon

Median/Midline Sagittal plane – the vertical plane which passes through the sagittal suture of the skull and through the midline of the body dividing the body into right and left halves.

ParaSagittal plane –any vertical plane parallel to the median sagittal plane.

Coronal plane –any vertical plane perpendicular to the median sagittal plane and parallel to the vertical plane through the coronal suture of the skull.

With CT scanning, factors can be altered for better resolution of different body parts.

e.g. Referring to the images enclosed, the scanner was set to optimally visualize mediastinal structures (1-4A), and lung parenchyma in (1-4B)

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Normal Chest anatomy on Axial Computed Tomography

Key:

1. Pectoralis major muscle

2. Pectoralis minor muscle

3. Sternum

4. Clavicle

5. Rib

6. Humeral head

7. Scapula

8. Vertebral body

9. Thyroid gland

10. Trachea

11. Esophagus

12. Subclavian artery

13. Carotid artery

14. Innominate (brachialcephalic) artery

15. Innominate vein

16. Superior vena cava (SVC

• Aortic arch

• Ascending aorta

• Descending aorta

• Azygos vein

* Carina (tracheal bifurcation)

21. Pulmonary artery

22. Main stem bronchus

23. Right ventricular outflow tract

24. Left atrium

25. Right atrium

26. Left ventricle

27. Right ventricle

28A. Pulmonary veins

28B. Inferior vena cava (IVC)

29. Diaphragm

• Liver

31. Spleen

32. Stomach

33. Kidney

34. Lung –upper lobe

35. Lung –right middle lobe

36. Lung –lower lobe

37. Major (oblique) fissure

38. Minor (horizontal) fissure

39. Segmental bronchus

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Computed Tomography1A

Key:



3. Sternum

4. Clavicle

5. Rib

6. Humeral head

7. Scapula

8. Vertebral body

9. Thyroid gland

10. Trachea

11. Esophagus


13. Carotid artery


15. Innominate vein

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Computed Tomography1B

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Key:

10. Trachea

11. Esophagus

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Computed Tomography

Key:



3. Sternum

4. Clavicle

5. Rib

6. Humeral head

7. Scapula

8. Vertebral body

9. Thyroid gland

10. Trachea

11. Esophagus


13. Carotid artery


15. Innominate vein


17. Aortic arch

2A

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Key:



3. Sternum

5. Rib

11. Esophagus


17. Aortic arch

18. Ascending aorta


20. Azygos vein


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Computed Tomography

Key:

10. Trachea

11. Esophagus

34. Lung-upper lobe

36. Lung-lower lobe


2B

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Key:

* Carina (tracheal bifurcation)

22. Main stem bronchus


39. Segmental bronchus

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Computed Tomography

Key:

3. Sternum

5. Rib

7. Scapula

8. Vertebral body

11. Esophagus



20. Azygos vein



24. Left atrium

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Key:

3. Sternum

5. Rib

7. Scapula


18. Ascending aorta



24. Left atrium


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Computed Tomography

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Key:

11. Esophagus






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Key:






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Computed Tomography

Key:

3. Sternum

5. Rib

8. Vertebral body

11. Esophagus


24. Left atrium

25. Right atrium

26. Left ventricle

27. Right ventricle



29. Diaphragm

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Key:


26. Left ventricle



29. Diaphragm

30. Liver

31. Spleen

33. Kidney

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Computed Tomography

Key:

11. Esophagus

29. Diaphragm

35. Lung- right middle lobe

36. Lung- lower lobe


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Key:

32. Stomach

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Normal MRI ChestMagnetic Resonance Imaging (MRI) utilizes changing magnetic and electrical fields to obtain images of a patient. Factors can be altered to enhance resolution of different structures thus blood for example can look bright white or dark black.

Among the advantages of MRI are:

1. X-rays and the attendant hazards of ionizing radiation are not present.

2. Scans in multiple different projections e.g. oblique, sagittal, coronal, axial can be obtained with ease.

Refer to films:

Film 1 -Sagittal oblique MRI angiogram chosen to best demonstrate the aortic arch.

Film 2&3 -Axial sections

Film 4&5 -Sagittal oblique MRI angiogram chosen to best demonstrate the coronary arteries

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MRI 13

Normal Sagittal MRI Chest

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Normal Axial MRI ChestMRI 2a

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Normal MRI ChestMRI 2b

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Normal MRI Chest

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MRI 3a

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Normal MRI ChestMRI 3b

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Normal Parasagittal MRI ChestMRI 4

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Normal MRI ChestMRI 4

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Normal MRI Chest

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Conclusion of Living anatomy of the chest

Congratulations! You have completed this module.

You worked through many anatomic diagrams and labeled chest x-rays, bronchograms, angiograms, CT scans & MRI images. You saw the normal and also some Abnormal images to peak your interest. Radiology is ideally suited to image not only normal anatomy, but more importantly from a clinical diagnostic standpoint, abnormal anatomy & pathology.

Wishing you a joy-filled career and life long love of learning. Gill

With grateful thanks to Pamela Lepkowski, Education Coordinator, HarvardMedical School & Assistant extraordinaire for her outstanding work on this Independent study module.

chest x-ray anatomy

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