The colloquial term “bird chest” is not a medical diagnosis but a descriptive phrase used to refer to noticeable irregularities in the chest wall’s structure. This appearance often relates to conditions that affect the sternum, or breastbone, and the ribs attached to it. While the phrase is informal, it signals an underlying structural variation. This variation can range from a purely cosmetic difference to one that potentially impacts internal organ function.
The Two Primary Forms of Chest Wall Deformity
The physical appearance described as a “bird chest” typically refers to one of two main chest wall deformities: Pectus Excavatum or Pectus Carinatum. Pectus Excavatum, often called “sunken chest” or “funnel chest,” is the most common anterior chest wall deformity. In this condition, the sternum and the attached cartilage sink inward, creating a depression in the center of the chest. This deformity gives the chest a concave appearance.
Pectus Carinatum, the second most common deformity, is sometimes referred to as “pigeon chest” because of its protruding shape. Unlike the sunken chest, Pectus Carinatum involves an outward protrusion of the breastbone and costal cartilage. The chest wall is pushed forward, causing it to jut out. The degree of protrusion or indentation can vary greatly, and some patients may have a mixed or asymmetrical presentation.
How These Deformities Develop
The development of these chest wall variations is attributed to an abnormal growth pattern of the costal cartilage, the connective tissue that connects the ribs to the sternum. This growth disturbance forces the sternum either inward or outward. Although Pectus Excavatum and Pectus Carinatum are often present from birth, they frequently become more noticeable during periods of rapid skeletal growth, such as adolescent growth spurts.
Genetic predisposition plays a significant role in the occurrence of these deformities. Up to 53% of patients with Pectus Excavatum report a family history, suggesting a strong hereditary component. Furthermore, they are often associated with connective tissue disorders like Marfan syndrome and Ehlers-Danlos syndrome. These associations highlight that the underlying issue is related to systemic development.
Health Implications and Quality of Life
While the concern for many individuals is the visual appearance, these structural variations can lead to physiological and psychological consequences. In cases of severe Pectus Excavatum, the inward displacement of the sternum can physically compress the heart and lungs. This compression may restrict the heart’s ability to fill with blood efficiently, potentially leading to reduced cardiac output, especially during exercise.
The restriction on lung expansion can result in symptoms like shortness of breath and a decreased tolerance for physical activity. Pectus Carinatum is less likely to affect heart and lung function directly, though some patients report chest pain or shortness of breath with exertion. Beyond the physical symptoms, the cosmetic appearance of both deformities can significantly impact a person’s quality of life. The visible difference can cause substantial emotional distress, self-consciousness, and social anxiety, often driving the desire for correction.
Diagnosis and Treatment Options
Diagnosing a chest wall deformity begins with a thorough physical examination and a detailed medical history. Imaging tests are used to accurately measure the extent of the deformity and its effect on internal organs. A computed tomography (CT) scan is commonly used to calculate the Haller index, a ratio that compares the chest width to the depth, helping to determine the severity of Pectus Excavatum.
Additional diagnostic tools include an echocardiogram to evaluate heart structure and function, and pulmonary function tests to measure lung capacity. Treatment decisions depend on the severity of the condition and the presence of symptoms. Non-surgical options include physical therapy to improve posture and, for Pectus Carinatum, external bracing that applies pressure to gradually reshape the protruding chest wall.
For moderate to severe cases, particularly Pectus Excavatum with functional limitations, surgical correction may be recommended. The minimally invasive Nuss procedure involves inserting a curved metal bar beneath the sternum to push it into a corrected position for two to three years. The Ravitch procedure is a traditional open surgery that involves removing the abnormally grown cartilage before repositioning the breastbone. These interventions aim to alleviate internal pressure and improve both physiological function and self-esteem.