A sunken or “caved-in” appearance of the chest is medically known as Pectus Excavatum. This condition represents the most frequent congenital deformity of the chest wall. While the sight of a depressed sternum can be alarming, the condition is often benign, though its severity varies widely. Understanding the anatomical structure and potential implications is the first step in addressing this physical difference.
Defining Pectus Excavatum
Pectus excavatum is a structural malformation characterized by an inward growth of the sternum (breastbone) and the connected ribs. This growth results in a concave depression in the center of the chest, often called funnel chest. The deformity typically involves the cartilages of the third through the seventh ribs. It is a common congenital issue, occurring more frequently in males than in females.
The depression can appear symmetric, forming a uniform scoop, or more commonly, asymmetric, resulting in a deeper indentation on one side. Severity is objectively classified using the Haller Index, a measurement derived from cross-sectional imaging like a CT scan. This index divides the maximum horizontal width of the ribcage by the narrowest distance between the sternum and the spine. A normal chest has an index of 2.5 or less, while a measurement greater than 3.25 is considered severe and often triggers consideration for corrective intervention.
Developmental Origin and Causes
The exact mechanism behind pectus excavatum remains unknown, but it is classified as a developmental abnormality of the chest wall. The prevailing theory suggests the condition arises from excessive and uneven growth of the costal cartilage, the flexible tissues connecting the ribs to the sternum. This overgrowth creates a force that pushes the sternum inward, causing the characteristic sunken appearance. Although often present at birth, the deformity can become significantly more pronounced during periods of rapid skeletal growth, such as adolescence.
A strong genetic component is implicated, as a family history of pectus excavatum is present in approximately 25 to 40% of cases. This familial link suggests a hereditary factor, though a single responsible gene has not been identified. While most cases are isolated, the condition is sometimes associated with broader connective tissue disorders, including Marfan syndrome and Ehlers-Danlos syndrome. These associated conditions involve generalized weakness in structural proteins, which may contribute to the abnormal cartilage growth.
Physical and Functional Impact
The inward depression of the sternum mechanically reduces the space available for organs within the chest cavity, leading to physiological effects in moderate to severe cases. The heart is often physically displaced toward the left side and can be compressed between the sternum and the spine. This compression interferes with the heart’s ability to fill with blood efficiently, especially the right ventricle. This may result in a reduced stroke volume during physical exertion. The body compensates for this reduced output by increasing the heart rate, which can manifest as palpitations.
The mechanical pressure also restricts the full expansion of the lungs, especially during strenuous activity. This restriction leads to a reduction in lung volumes and a diminished capacity for deep breathing. Individuals with a pronounced chest indentation often report symptoms such as shortness of breath with exercise and decreased endurance compared to their peers. This reduced exercise tolerance is a common complaint, resulting from compromised heart and lung function.
The highly visible nature of the sunken chest can cause a significant psychological burden alongside cardiopulmonary symptoms. The physical difference often leads to self-consciousness and body image issues, especially during adolescence. This emotional distress may cause individuals to withdraw from social activities, such as sports. Therefore, the decision to seek correction is often motivated by the desire for physical symptom relief and the need to address the aesthetic and mental impact of the deformity.
Assessment and Correction Options
Initial evaluation begins with a thorough physical examination and a detailed review of the patient’s symptoms and family history. To accurately assess the deformity and its internal effects, a combination of imaging and functional tests is employed. A CT scan or MRI is often ordered to obtain precise cross-sectional images, allowing for the calculation of the Haller Index. An index exceeding 3.25 is a common threshold used by surgeons to determine candidacy for intervention.
Functional testing quantifies the impact on the heart and lungs, even if the deformity appears mild. This process includes a cardiology assessment, often involving an echocardiogram to visualize heart movement and compression, and an electrocardiogram (ECG). Pulmonary function tests measure lung volumes and the capacity for air exchange. Exercise testing can further demonstrate reduced oxygen pulse and maximum oxygen uptake, which are objective signs of impaired cardiorespiratory function.
For patients with mild or flexible deformities, a non-surgical approach using Vacuum Bell Therapy (VBT) is sometimes considered. This treatment involves placing a suction cup device on the chest wall and creating a vacuum to physically lift the sternum outward over time. VBT requires sustained, consistent use, often over 12 to 15 months. It is most effective in younger patients whose chest walls are still pliable and offers a non-invasive alternative to surgery.
When functional impairment is significant or the deformity is severe, surgical correction is the standard treatment pathway. The most common modern procedure is the minimally invasive repair of pectus excavatum, known as the Nuss Procedure. This technique involves inserting a custom-shaped convex metal bar through small incisions on the sides of the chest. The bar is then flipped to press the sternum outward and correct the depression, remaining in place for approximately two to four years before surgical removal.
The traditional open repair, called the Ravitch Procedure, is performed less frequently but remains an option for complex or asymmetric cases. This procedure involves making a larger incision, removing the overgrown costal cartilage, and then repositioning the sternum. The sternum is supported with temporary internal structures. Regardless of the chosen path, the decision regarding correction should be made in consultation with a cardiothoracic specialist who weighs the objective severity against the patient’s symptoms and quality of life concerns.