The lungs are the primary organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the backbone on either side of the heart. Their function in the respiratory system is to extract oxygen from the atmosphere and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. Respiration is driven by different muscular systems in different species. Mammals, reptiles and birds use their musculoskeletal systems to support and foster breathing. In early tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, a mechanism still seen in amphibians. In humans, the primary muscle that drives breathing is the diaphragm. The lungs also provide airflow that makes vocalisation including speech possible.
A bronchus is a passage or airway in the lower respiratory tract that conducts air into the lungs. The first or primary bronchi to branch from the trachea at the carina are the right main bronchus and the left main bronchus. These are the widest bronchi, and enter the right lung, and the left lung at each hilum. The main bronchi branch into narrower secondary bronchi or lobar bronchi, and these branch into narrower tertiary bronchi or segmental bronchi. Further divisions of the segmental bronchi are known as 4th order, 5th order, and 6th order segmental bronchi, or grouped together as subsegmental bronchi. The bronchi, when too narrow to be supported by cartilage, are known as bronchioles. No gas exchange takes place in the bronchi.
Caroli disease is a rare inherited disorder characterized by cystic dilatation of the bile ducts within the liver. There are two patterns of Caroli disease: focal or simple Caroli disease consists of abnormally widened bile ducts affecting an isolated portion of liver. The second form is more diffuse, and when associated with portal hypertension and congenital hepatic fibrosis, is often referred to as "Caroli syndrome". The underlying differences between the two types are not well understood. Caroli disease is also associated with liver failure and polycystic kidney disease. The disease affects about one in 1,000,000 people, with more reported cases of Caroli syndrome than of Caroli disease.
Bronchiectasis is a disease in which there is permanent enlargement of parts of the airways of the lung. Symptoms typically include a chronic cough with mucus production. Other symptoms include shortness of breath, coughing up blood, and chest pain. Wheezing and nail clubbing may also occur. Those with the disease often get lung infections.
In medical or research imaging, an incidental imaging finding is an unanticipated finding which is not related to the original diagnostic inquiry. As with other types of incidental medical findings, they may represent a diagnostic, ethical, and philosophical dilemma because their significance is unclear. While some coincidental findings may lead to beneficial diagnoses, others may lead to overdiagnosis that results in unnecessary testing and treatment, sometimes called the "cascade effect".
Atelectasis is the partial collapse or closure of a lung resulting in reduced or absence in gas exchange. It is usually unilateral, affecting part or all of one lung. It is a condition where the alveoli are deflated down to little or no volume, as distinct from pulmonary consolidation, in which they are filled with liquid. It is often referred to informally as a collapsed lung, although more accurately it usually involves only a partial collapse, and that ambiguous term is also informally used for a fully collapsed lung caused by a pneumothorax.
A chest radiograph, chest X-ray (CXR), or chest film is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common film taken in medicine.
Bronchiolitis obliterans (BO), also known as obliterative bronchiolitis, constrictive bronchiolitis and popcorn lung, is a disease that results in obstruction of the smallest airways of the lungs (bronchioles) due to inflammation. Symptoms include a dry cough, shortness of breath, wheezing and feeling tired. These symptoms generally get worse over weeks to months. It is not related to cryptogenic organizing pneumonia, previously known as bronchiolitis obliterans organizing pneumonia.
Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterised by an exaggerated response of the immune system to the fungus Aspergillus. It occurs most often in people with asthma or cystic fibrosis. Aspergillus spores are ubiquitous in soil and are commonly found in the sputum of healthy individuals. A. fumigatus is responsible for a spectrum of lung diseases known as aspergilloses.
Aspergillosis is a fungal infection of usually the lungs, caused by the genus Aspergillus, a common mould that is breathed in frequently from the air, but does not usually affect most people. It generally occurs in people with lung diseases such as asthma, cystic fibrosis or tuberculosis, or those who are immunocompromised such as those who have had a stem cell or organ transplant or those who take medications such as steroids and some cancer treatments which suppress the immune system. Rarely, it can affect skin.
Peribronchial cuffing, also referred to as peribronchial thickening or bronchial wall thickening, is a radiologic sign which occurs when excess fluid or mucus buildup in the small airway passages of the lung causes localized patches of atelectasis. This causes the area around the bronchus to appear more prominent on an X-ray. It has also been described as donut sign, considering the edge is thicker, and the center contains air.
Diffuse panbronchiolitis (DPB) is an inflammatory lung disease of unknown cause. It is a severe, progressive form of bronchiolitis, an inflammatory condition of the bronchioles. The term diffuse signifies that lesions appear throughout both lungs, while panbronchiolitis refers to inflammation found in all layers of the respiratory bronchioles. DPB causes severe inflammation and nodule-like lesions of terminal bronchioles, chronic sinusitis, and intense coughing with large amounts of sputum production.
A lung nodule or pulmonary nodule is a relatively small focal density in the lung. A solitary pulmonary nodule (SPN) or coin lesion, is a mass in the lung smaller than three centimeters in diameter. A pulmonary micronodule has a diameter of less than three millimetres. There may also be multiple nodules.
Ground-glass opacity (GGO) is a finding seen on chest x-ray (radiograph) or computed tomography (CT) imaging of the lungs. It is typically defined as an area of hazy opacification (x-ray) or increased attenuation (CT) due to air displacement by fluid, airway collapse, fibrosis, or a neoplastic process. When a substance other than air fills an area of the lung it increases that area's density. On both x-ray and CT, this appears more grey or hazy as opposed to the normally dark-appearing lungs. Although it can sometimes be seen in normal lungs, common pathologic causes include infections, interstitial lung disease, and pulmonary edema.
In radiology, honeycombing or "honeycomb lung" is the radiological appearance seen with widespread pulmonary fibrosis and is defined by the presence of small cystic spaces with irregularly thickened walls composed of fibrous tissue. Dilated and thickened terminal and respiratory bronchioles produce cystic airspaces, giving a honeycomb appearance on chest x-rays. Honeycomb cysts often predominate in the peripheral and pleural/subpleural lung regions regardless of their cause.
Emphysema is any air-filled enlargement in the body's tissues. Most commonly emphysema refers to the permanent enlargement of air spaces (alveoli) in the lungs, and is also known as pulmonary emphysema.
A lung cavity or pulmonary cavity is an abnormal, thick-walled, air-filled space within the lung. Cavities in the lung can be caused by infections, cancer, autoimmune conditions, trauma, congenital defects, or pulmonary embolism. The most common cause of a single lung cavity is lung cancer. Bacterial, mycobacterial, and fungal infections are common causes of lung cavities. Globally, tuberculosis is likely the most common infectious cause of lung cavities. Less commonly, parasitic infections can cause cavities. Viral infections almost never cause cavities. The terms cavity and cyst are frequently used interchangeably; however, a cavity is thick walled, while a cyst is thin walled. The distinction is important because cystic lesions are unlikely to be cancer, while cavitary lesions are often caused by cancer.
A focal lung pneumatosis is an enclosed pocket of air or gas in the lung and includes blebs, bullae, pulmonary cysts, and lung cavities. Blebs and bullae can be classified by their wall thickness.
The gloved finger sign is a radiologic sign observed on chest radiographs or CT scans that indicates the presence of mucoid impaction in the lungs. Mucoid impaction occurs when bronchi become dilated and filled with mucus. This abnormality appears as branching tubular opacities projecting out from the hila towards the periphery of the lungs, resembling gloved fingers. The gloved finger sign has been observed in the imaging of several conditions, including bronchial atresia, cystic fibrosis, bronchiectasis, allergic bronchopulmonary aspergillosis, foreign body aspiration, benign tumors, and malignancies.
The small bowel feces sign is a radiological finding observed in radiological imaging studies, particularly in cases of small bowel obstruction. It is characterized by the presence of particulate matter resembling fecal material within the lumen of dilated small bowel loops. This sign is most commonly identified on computed tomography (CT) scans and, less frequently, on abdominal radiographs.
