Pectus excavatum, often called “funnel chest” or “sunken chest,” is a common congenital chest wall deformity where the breastbone, or sternum, appears sunken into the chest. This structural anomaly involves the abnormal shaping of the sternum and rib cage. While present at birth, the condition frequently becomes more noticeable during rapid growth periods, such as adolescence. It is considered the most common chest wall deformity, affecting approximately 1 in 150 to 1 in 1,000 births, with a higher prevalence in males.
Physical Characteristics of the Deformity
The defining feature of pectus excavatum is an inward depression of the sternum and sometimes adjacent ribs, resulting in a concave chest appearance. This depression varies significantly, from a subtle dip to a deep, narrow, or broad indentation. The deformity can be symmetrical, with the sternum sinking evenly, or asymmetrical, appearing deeper on one side. In some individuals, particularly younger children, the lower-most ribs may protrude outward, a phenomenon known as “flared ribs.” The condition often becomes more pronounced during puberty’s rapid growth spurts, continuing to deepen until around 18 years of age when most skeletal growth is complete.
Origins and Risk Factors
The precise cause of pectus excavatum is not fully understood; it is often considered an idiopathic developmental anomaly. One theory suggests it results from an irregular growth pattern of the cartilage connecting the ribs to the breastbone, causing the sternum to be pulled inward. A significant genetic component is recognized, as the condition frequently runs in families, indicating a hereditary predisposition. Pectus excavatum can also be associated with certain genetic syndromes or connective tissue disorders, including Marfan syndrome, Ehlers-Danlos syndrome, Noonan syndrome, and Poland syndrome. Additionally, scoliosis is often found alongside pectus excavatum.
How the Body is Affected
The inward displacement of the sternum can physically affect internal organs, particularly the heart and lungs, by reducing chest cavity space. In severe cases, the depressed sternum can compress or displace the heart, often shifting it to the left, which can hinder its ability to pump blood efficiently, potentially leading to symptoms like palpitations or an irregular heartbeat. Lung function can also be compromised, as reduced space limits full expansion and lung capacity. Individuals may experience shortness of breath, especially during physical exertion, and decreased stamina or exercise intolerance. Fatigue and chest pain are also common physical symptoms, intensifying with progression or increased activity.
Pectus excavatum can also impact psychological well-being. Body image concerns, self-consciousness, and anxiety are common, particularly among adolescents, leading some to avoid activities that expose their chest, such as swimming or sports.
Diagnosis and Associated Findings
Pectus excavatum is typically diagnosed through a physical examination, where a healthcare provider assesses the chest for its characteristic sunken appearance and indentation depth. To evaluate the deformity’s severity and its potential impact on internal organs, various diagnostic tools are employed.
Chest X-rays can reveal heart displacement. Computed tomography (CT) scans provide detailed cross-sectional images for precise measurement of the deformity, often using the Haller index; a Haller index greater than 3.25 often indicates a severe case. Pulmonary function tests assess lung capacity and efficiency, while echocardiograms evaluate heart function, its position, and check for any associated cardiac issues like murmurs or valve prolapse.