Art of Anatomy of the Lungs
Ashley Davidoff MD Copyright 2015
In this first part of the series on the anatomy of lungs we emphasize principles, and outline how structure is integrated with function, disease and diagnosis. The lungs are two huffing and puffing sponge-like organs that dominate the chest cavity, essential in their function as the principal structures of respiration.
“A Breath of Fresh Air in the Lungs and Airways”
shows a 3D image of the lungs created using CT scan technology
“The Lungs Breathing in the Rib Jungle CT-Scan”
show phases of respiration surrounded by the rib cage which has intimate involvement in the movement of the chest and lungs
In this first part of the series on the anatomy of lungs we emphasize principles, and outline how structure is integrated with function, disease and diagnosis.
The unique structural characteristics of the lungs include their:
- dominance in the chest cavity
- ability to accommodate the entire cardiac output with every heartbeat
- asymmetric nature
- irregular and dichotomous branch pattern of the bronchovascular bundle
- tubular transport system, with a single system functioning for both delivery and removal
- spongy air-filled character
- pyramidal or cone shape
- dual blood supply
The unique functional aspects include
- ability to move air efficiently
- ability to exchange gases efficiently
The Common diseases that affect the lung include
- Infections such as pneumonia and bronchitis
- Neoplasms such as malignant carcinoma
- Mechanical disorders such as emphysema
- Circulatory disorders such as pulmonary embolism, pulmonary hypertension, and cor pulmonale
- Immune disorders such as allergic asthma
The tools used for diagnosis include
- Clinical history taking and clinical examination
- Lab investigation including blood gases and lung function tests
- Imaging studies including chest X-ray and CT scan
Treatment options in the pharmacological armamentarium include
- Antibiotics for infections
- Chemotherapeutic agents for malignancies
- Smooth muscle relaxants for diseases that cause muscle spasm
- Anticoagulants for pulmonary embolism and antifailure therapy for cor pulmonale
- Surgical options are widely used for diseases such as bronchiectasis, malignancy, and pleural disease
- Minimally invasive options are used to plug and cement emphysematous lungs, coil arteriovenous malformations, drain pleural effusions and pneumothoraces.
An understanding of the unique anatomy and physiology of the lungs brings comprehension of how diseases will affect the lungs, and how these changes will be manifest clinically, in the lab, and on imaging studies. Consequently understanding extends to the diagnosis and then treatment of disorder in the lungs.
Structural features
A Page from the Story of the Lungs
The AiA collage shows the lung in multiple facets including the rhythmic motion of inspiration and expiration (first and second images top row) an anatomical specimen, (top right) a 3D view (first left middle row) an artistic rendering of the secondary lobule (middle of the middle row) an artistic rendering of the small airways (middle row right and bottom row left) and the alveolus (last row middle and right image).
Dominance in the chest cavity
“Chest of Fruit” – dominated by the lungs
This AiA rendition of the heart and lungs uses the shape of fruit and vegetables to create an image of the chest. The lungs are made of grapes, the pulmonary arteries of carrots, the ribs of banana peel and the heart is made of a red pepper. This image reflects the concept of the parts making up the whole.
Ability to accommodate the entire cardiac output with every heartbeat
One Beat – An Entire Cardiac Output in the Lungs
The AiA rendering uses the implied microscopic capillary connections in the pulmonary circulation and gives the intimacy a human context. They transport a whole cardiac output within one beat of the heart. The pulmonary circulation consists of a pulmonary arterial system that receives deoxygenated (“blue”) blood from the right side of the heart and transports the blood to the lungs where it is oxygenated at the capillary level. The pulmonary veins transport the oxygenated (“red”) blood back to the left atrium. The artistic rendering shows the delicate connections between the two circulations.
Asymmetric nature of the lungs and irregular and dichotomous branch pattern of the bronchovascular bundle
Asymmetric Branching and the Ginkgo Tree
The AiA rendering is from a coronal 3D reformat of a chest CT shows normal lungs and airways. The right lung has 3 lobes while the left lung has two lobes. The top left image shows the irregular and dichotomous branch pattern. At the first branch point, the right bronchus is short and fat and the left long and thin. The CT scan is then turned upside down in the top right image so that tracheobronchial system looks like a tree stripped of leaves in the winter. With digital rendering the image is shaped so the lungs reflect the character of the ginkgo leaves as part of the Gingko tree.
Function Exchange of Gases
“Alveolus Cells and Capillaries of the Lung”
shows an alveolus with single cell lining and associated arteriole, capillary and venous circulation. The cool fresh air flows into the alveolus, and oxygen flows into the blue blooded arteriole converting into a red blooded venule. A breeze of carbon dioxide flows through the single celled alveolus and into the airways for expiration
The Common Diseases of the Lungs
“The Big and Black Lungs of Emphysema”
shows the normal sized pink lungs surrounded by the progressively enlarging gray and then black lungs of smoking related emphysema. If only they could go back to they they were!
shows normal structure of terminal airways and alveoli on the left and emphysema with dilated respiratory bronchioles and alveoli. The left sided image is an artistic rendering of the normal terminal bronchioles and alveoli and shows normal lung architecture. The right image is an artistic rendering showing the ravages of the disease called emphysema caused by smoking. In this disease the small airways and alveoli lose their elasticity and get stretched evolving into larger and larger structures. These small airways look like big berries on a dilated stalk (respiratory bronchiole)
“Emphysema; Lungs and Small Airways too Big”
shows the principle of structures that are too big and therefore they cannot perform their function optimally. The left sided image is a CT scan that shows normal lung architecture. The right image is a CT scan showing the ravages of the disease called emphysema caused by smoking. In emphysema the small airways and alveoli lose their elasticity and get stretched evolving into larger and larger structures. These small airways look like big black holes in the lung and the appearance is also referred to a “Swiss cheese”. The art piece tells an educational story but also reflects the Goldilocks principle about size – just right and not too big!
The tools used for diagnosis include
- Clinical history taking and clinical examination
- Lab investigation including blood gases and lung function tests
- Imaging studies including chest X-ray and CT scan
“Diagnosis in the Heart and Lungs”
The AiA rendering of a chest X-ray and a stethoscope shows the initial essential sequences required for the diagnosis of lung and heart disease. In this image all sensitivities of the expert clinician come together to enable a preliminary diagnosis to be made. The stethoscope is symbolic icon of audible clues and the x-ray is symbolic of using visual acuity in diagnosis. The artistic element of this piece is the impressionistic feel and the whimsical nature of the stethoscope trying to examine the depths of the chest which is also the function of the chest X-ray
“Imaging the Lungs in a Nutshell”
shows the many ways radiology can image the lungs, including X-ray, CT-scan, and angiography.
The AiA rendering of a chest CT scan reconstructed in 3D shows the lung and heart beyond the skin. The beautiful color provides a quiet and restful ambiance as the heart continues its quiet rhythms among the mostly silent and life sustaining movement of air in the airways.
Treatment options
Antibiotics for infections
Chemotherapeutic agents for malignancies
Smooth muscle relaxants for diseases that cause muscle spasm
Anticoagulants for pulmonary embolism and antifailure therapy for cor pulmonale
Surgical options are widely used for diseases such as bronchiectasis, malignancy, and pleural disease
Minimally invasive options are used to plug and cement emphysematous lungs, coil arteriovenous malformations, drain pleural effusions and pneumothoraces.
- Revised post from TheCommonVein.com
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