The term “barrel chest” has been used frequently in medical literature, typically to describe a finding during a physical examination. It is also a term used in text books and clinical papers describing an attribute that is suggestive of a clinical process.
But what does barrel chest actually mean?
The shape of the chest is dictated by the rib cage system, which encloses the heart and the lungs. At rest, the ribs are at an angle sloping downward from the back to the front. In rare instances the ribs are not oriented at a downward angle but are instead in a horizontal position. This orientation increases the diameter of the chest, thus giving it the appearance of a “barrel.”
What are some instances where this chest presentation occurs?
This physical presentation is prevalent in some populations. For example, individuals who live in high altitudes above 5,000 meters (about 15,000 feet) — i.e., the Andes and the Himalayas -- typically present with a barrel chest. The natives of those areas have developed this chest variation as a compensatory mechanism at the high altitude (and thinner air), along with a high count of red blood cells (polycythemia), which provides greater oxygen availability and delivery.
Body builders work hard to build up their pectoral muscles, and that muscular hypertrophy will ultimately create a barrel chest, as well.
When is a barrel chest a sign of a disease process?
Chronic obstructive pulmonary disease (COPD) is the most common instance in which a barrel chest will occur. In these cases, it’s a sign of the lungs being over-expanded. This is caused by the loss of elasticity and results in the person having hyper-inflated lungs.
Too much air collects in the lungs and the movement of air in and out is impeded. In these instances, the diaphragm, the most important muscle involved in the inspiration of air, is not a normal dome-shape but is flattened, making it hard for the muscle to work efficiently. Emphysematous people get used to this impairment and compensate by using muscles in the ribs and the neck to assist in the breathing process. This may work when someone is at rest, but it becomes a serious limiting factor during exercise, when the breathing rate has to increase to handle the demands of the workout.
The barrel chest is a physical sign particularly associated with emphysema. It’s an important description, because not all patients with COPD have the barrel chest feature of emphysema. This implication identifies why it’s important to describe someone with a “barrel chest” during a physical examination.
Other disease processes
One rare condition called acromegaly involves excess levels of growth hormone and that excess may manifest itself with a barrel chest finding.
Osteoarthritis causes stiffening of the joints. This can occur in the joints where the ribs attach to the sternum and the spine. The resulting barrel chest is a similar presentation in the upper torso to the appearance of the finger joints as someone ages with this condition. The ribs become fixed in their most expanded position, giving the appearance of a barrel chest, and this can also cause respiratory limitations during exercise.
Cystic fibrosis is a genetic condition that causes the mucus in the lungs to be more tenacious and difficult to mobilize. That process also limits the function of the lungs and can result in barrel chest. In most cases, cystic fibrosis is diagnosed before a child is 2 years old and as the disease progresses, it affects lung development. This results in the person having to expend extra effort daily as they try to mobilize their secretions.
Children with severe asthma struggle with airways that are persistently narrowed. This physical challenge results in trapping of air after exhalation, and that can cause a barrel chest. This finding is more critical in children with asthma who are in a growth and development state. Experts suggest that the presence of barrel chest can slow down the growth rates in these children.
Though modern medicine relies on continuous advancements in diagnostic technologies, the barrel chest is an example of a clear physical presentation that is immediately recognized as a sign of one of several possible diseases.
Eli Hendel, M.D. is a board-certified Internist and pulmonary specialist with board certification in Sleep Medicine. He is an Assistant Clinical Professor of Medicine at Keck-University of Southern California School of Medicine, Qualified Medical Examiner for the State of California Department of Industrial Relations, and Director of Intensive Care Services at Glendale Memorial Hospital. His areas of expertise in private practice include asthma, COPD, sleep disorders, obstructive sleep apnea, and occupational lung diseases.