Pectus Carinatum

Pectus carinatum is a chest wall deformity characterized by anterior protrusion of the sternum and adjacent costal cartilages. It often becomes more noticeable during rapid growth in adolescence and can present with cosmetic concerns, musculoskeletal symptoms, or cardiopulmonary complaints. Early recognition allows timely counseling, structured monitoring, and intervention when appropriate.

This article reviews key concepts for clinicians and learners, including definitions and classification, basic pathophysiology, and the clinical significance of pectus carinatum. The sections are organized to support evidence-based assessment and choice of treatment.

Introduction

Pectus carinatum is one of the primary congenital chest wall deformities and is frequently identified in late childhood or adolescence. Although many cases are mild and primarily cosmetic, some individuals experience exercise intolerance, dyspnea on exertion, chest pain, or postural changes. Psychosocial impacts related to body image are common and may influence health seeking behavior and treatment goals.

The deformity results from abnormal growth of costal cartilages that displace the sternum anteriorly. Two predominant patterns are observed in clinical practice: a chondrogladiolar prominence involving the middle and lower sternum and a chondromanubrial prominence involving the upper sternum. Severity can vary from subtle contour changes to marked protrusion with asymmetry and rib flare.

Management ranges from observation and exercise-based strategies to dynamic compression bracing and operative correction in selected cases. Decisions depend on age, skeletal maturity, severity, symptoms, and patient preference. Multidisciplinary care involving pediatrics, thoracic surgery, physiotherapy, and psychology optimizes outcomes.

Definition and Overview

Meaning of Pectus Carinatum

Pectus carinatum refers to a protruding sternum with anterior displacement of the costal cartilages that produces a keel-shaped chest contour. The term contrasts with pectus excavatum, which features a posterior depression of the sternum.

Historical Background and Terminology

• The descriptor carinatum derives from the Latin carina meaning keel, reflecting the resemblance to a ship keel.
• Older literature used terms such as pigeon chest and pectus arcuatum for specific variants.

Epidemiology and Demographics

• Onset commonly occurs in late childhood, with rapid progression around the pubertal growth spurt.
• There is a male predominance in reported series and a tendency toward familial clustering.
• Associations include tall stature phenotypes and connective tissue disorders such as Marfan and Noonan syndromes.

Subtypes and Patterns

• Chondrogladiolar type: prominence of the body of the sternum with lower rib cartilage protrusion, often more amenable to bracing.
• Chondromanubrial type: prominence of the manubrium with a shorter, stiffer anterior chest wall, sometimes requiring operative strategies.
• Asymmetric or mixed variants: lateral displacement, rib flare, or rotation of the sternum producing uneven contours.

Comparison With Pectus Excavatum

Feature	Pectus Carinatum	Pectus Excavatum
Sternal position	Anterior protrusion	Posterior depression
Typical onset	Childhood with pubertal progression	Childhood with pubertal progression
Primary concerns	Cosmetic, exercise symptoms, posture	Cosmetic, exercise symptoms, potential cardiac displacement
First-line therapy	Dynamic compression bracing in skeletally immature patients	Vacuum bell in select cases or minimally invasive repair in symptomatic cases

Anatomy and Pathophysiology

Normal Anatomy of the Chest Wall

The chest wall is composed of the sternum, ribs, costal cartilages, thoracic vertebrae, and associated muscles that together form a flexible yet protective framework around the thoracic organs. The sternum consists of three main parts: the manubrium, body (gladiolus), and xiphoid process. These structures are connected by costal cartilages that allow for elastic movement during respiration. The intercostal muscles, diaphragm, and accessory respiratory muscles contribute to the mechanics of breathing by altering thoracic volume.

Structural Abnormalities in Pectus Carinatum

In pectus carinatum, the costal cartilages grow abnormally, pushing the sternum outward and creating a convex anterior chest wall. The deformity can be symmetric or asymmetric depending on which costal cartilages are overgrown. The rigidity of the sternum and cartilage varies among individuals, influencing both the appearance and potential response to conservative therapy such as bracing. The anterior displacement of the sternum may lead to compensatory changes in adjacent ribs and musculature, sometimes accompanied by flattening of the lateral chest walls.

Biomechanical and Developmental Factors

The underlying mechanism is believed to involve unbalanced growth between the anterior and posterior elements of the rib cage during development. Excessive anterior chondral growth exerts outward pressure on the sternum, leading to protrusion. This imbalance may also alter respiratory mechanics by restricting chest wall compliance and contributing to inefficient breathing in severe cases. Musculoskeletal adaptations, including scapular protraction and kyphotic posture, may develop as compensatory changes over time.

Associated Musculoskeletal or Connective Tissue Disorders

• Pectus carinatum frequently coexists with generalized musculoskeletal abnormalities such as scoliosis or spinal kyphosis.
• Connective tissue disorders like Marfan syndrome, Ehlers-Danlos syndrome, and Noonan syndrome are often associated due to underlying defects in collagen or fibrillin synthesis.
• Patients with these syndromes tend to exhibit hypermobility, tall stature, and a high incidence of other chest wall deformities.

Classification and Types

Chondrogladiolar Type

This is the most common variety of pectus carinatum, involving the middle and lower portions of the sternum. The protrusion is caused by abnormal anterior growth of the fourth to seventh costal cartilages. The deformity is usually flexible in childhood but may stiffen as skeletal maturity approaches. Because of its pliability, this type often responds favorably to dynamic compression bracing when diagnosed early.

Chondromanubrial Type

The chondromanubrial form is less common but typically more rigid and difficult to correct non-surgically. It involves the upper sternum and first to third costal cartilages, leading to an angulated chest contour and limited chest wall compliance. Surgical correction, such as a modified Ravitch or Abramson procedure, is often indicated for severe or symptomatic cases.

Mixed or Asymmetric Variants

Some individuals present with a combination of upper and lower sternal protrusion or lateral asymmetry. The asymmetry may result in rotation of the sternum, uneven rib flare, or localized prominence on one side of the chest. These variants pose greater diagnostic and treatment challenges, often requiring customized orthotic designs or individualized surgical planning.

Comparison with Pectus Excavatum

Although both conditions result from abnormal cartilage growth, they differ in the direction of sternal displacement. Pectus carinatum is characterized by anterior protrusion, while pectus excavatum shows posterior depression of the sternum. Both conditions may coexist in rare mixed deformities, creating a complex chest wall contour. Understanding these differences is important for accurate diagnosis and for determining appropriate management strategies.

Etiology and Risk Factors

Genetic and Familial Factors

Pectus carinatum is believed to have a strong hereditary component, as it frequently appears in families with a history of chest wall deformities. Studies suggest an autosomal dominant pattern with variable expressivity, though the precise genetic mutations have not been clearly identified. Family members may also exhibit related skeletal anomalies, including scoliosis or pectus excavatum, reinforcing the role of inherited connective tissue characteristics.

Developmental Abnormalities in Costal Cartilage

The principal mechanism underlying pectus carinatum involves overgrowth of the costal cartilages that connect the ribs to the sternum. This disproportionate growth pushes the sternum outward, resulting in the characteristic protrusion. The exact cause of this overgrowth remains uncertain, but it may relate to localized metabolic disturbances in cartilage formation, altered collagen structure, or mechanical imbalances during thoracic development.

Postural and Growth-Related Factors

Rapid linear growth during adolescence can accentuate pre-existing chest wall irregularities. Poor posture, especially sustained kyphotic positioning, can influence the visual prominence of the deformity. In some cases, muscular imbalance between the anterior and posterior thoracic musculature contributes to the asymmetry or worsening of the protrusion during growth spurts.

Associated Syndromes

• Marfan Syndrome: Characterized by tall stature, long limbs, and joint hypermobility, this connective tissue disorder is often associated with pectus carinatum due to fibrillin-1 gene mutations affecting skeletal elasticity.
• Noonan Syndrome: Caused by genetic mutations affecting the RAS-MAPK pathway, this syndrome may present with chest wall deformities, cardiac defects, and distinctive facial features.
• Morquio Syndrome (Mucopolysaccharidosis Type IV): A lysosomal storage disorder leading to skeletal dysplasia, where abnormal cartilage and bone growth contribute to chest wall deformities such as pectus carinatum.
• Ehlers-Danlos Syndrome: Defective collagen synthesis in this condition results in joint laxity and structural weakness of connective tissues, predisposing individuals to chest wall abnormalities.

Clinical Features

Physical Appearance

The hallmark of pectus carinatum is a visible and palpable anterior protrusion of the sternum and adjacent costal cartilages. The deformity can vary in severity from mild elevation to a prominent keel-shaped chest. In symmetric cases, the entire sternum projects forward, while in asymmetric cases, one side may appear more elevated, often accompanied by rib flare. Shoulder protraction and mild thoracic kyphosis are common secondary postural changes.

Respiratory and Cardiovascular Symptoms

• Some patients report dyspnea on exertion due to decreased chest wall compliance or mechanical restriction during deep inspiration.
• Exercise intolerance may arise from inefficient respiratory mechanics rather than true pulmonary dysfunction.
• Occasional chest pain, palpitations, or fatigue can occur, particularly in more rigid deformities, although significant cardiac compression is rare.

Psychological and Cosmetic Impact

Beyond physical manifestations, pectus carinatum often carries profound psychosocial implications. Adolescents, in particular, may experience distress related to self-image, leading to social withdrawal, reduced participation in sports, and lowered confidence. Body image dissatisfaction is a major factor motivating treatment, even in the absence of physiological impairment. Counseling and reassurance form an important part of holistic management.

Associated Musculoskeletal Findings

• Increased incidence of scoliosis and spinal asymmetry.
• Postural abnormalities such as rounded shoulders and forward head posture.
• Occasional presence of chest wall tenderness or tightness in the pectoral region.

Clinical Variability

The degree of deformity, rigidity of the chest wall, and associated symptoms differ widely among patients. In some individuals, the protrusion remains flexible and reducible under pressure, whereas in others, it becomes firm and resistant to manipulation. Such differences are key considerations in determining the potential effectiveness of orthotic treatment versus surgical correction.

Diagnosis

Clinical Evaluation

Diagnosis of pectus carinatum begins with a thorough clinical examination and detailed medical history. The clinician assesses the onset, rate of progression, family history, and the presence of symptoms such as shortness of breath or exercise intolerance. Observation of the chest wall contour in both standing and supine positions provides valuable information regarding flexibility and symmetry of the deformity. The examiner evaluates whether the prominence is centered or shifted laterally and measures chest expansion during respiration to assess functional impact.

In addition to visual inspection, palpation of the costal cartilages helps determine rigidity. The degree of sternal protrusion and any associated rib flare are documented. Assessment of posture, spinal curvature, and shoulder alignment should also be performed, as many patients exhibit compensatory postural adaptations. A flexible deformity that flattens under gentle manual pressure typically responds better to bracing therapy than a rigid chest wall.

Assessment of Severity and Symmetry

The severity of pectus carinatum is graded based on the prominence of the sternum and the degree of asymmetry. Some clinicians use calipers or external 3D scanning systems to quantify protrusion height and chest wall symmetry. The deformity can be unilateral or bilateral, with unilateral cases sometimes mimicking rib or costal cartilage swelling. Consistent measurements over time help monitor treatment progress, especially during adolescence when growth-related changes can alter severity rapidly.

Imaging and Investigations

• Chest X-Ray: Provides a general overview of thoracic shape and helps rule out other skeletal anomalies. It may show increased anteroposterior chest diameter and anterior displacement of the sternum.
• Computed Tomography (CT) or Magnetic Resonance Imaging (MRI): Used to evaluate internal thoracic anatomy, degree of sternal protrusion, and the relationship of the heart and lungs to the chest wall. The Haller Index, calculated from CT scans, offers an objective ratio comparing the transverse diameter to the anteroposterior depth of the chest.
• 3D Surface Scanning and Photogrammetry: Modern techniques used to document deformity without radiation exposure. These methods are particularly useful for treatment planning and assessing progression during bracing.
• Cardiopulmonary Function Tests: Pulmonary function testing and echocardiography may be performed in symptomatic patients to evaluate lung capacity and detect any cardiac displacement or compression.

Differential Diagnosis

• Pectus Excavatum: Characterized by depression rather than protrusion of the sternum; however, mixed forms may exist.
• Poland Syndrome: Involves unilateral absence of pectoral muscles, leading to chest asymmetry that may resemble carinatum on one side.
• Scoliosis-Related Chest Deformity: Lateral curvature of the spine can distort the thoracic cage and cause asymmetric prominence of ribs or sternum.
• Costal Cartilage Tumors or Inflammatory Lesions: Rare conditions that can produce localized swelling but are distinguishable by imaging and clinical context.

Complications and Associated Conditions

Respiratory Restriction

In mild cases, respiratory function remains largely normal; however, severe or rigid deformities may limit chest wall compliance, reducing tidal volume and contributing to exertional breathlessness. This occurs because outward sternal rigidity can impede normal expansion of the thoracic cavity during inspiration. Long-term mechanical inefficiency may lead to compensatory overuse of accessory respiratory muscles.

Postural Abnormalities

Pectus carinatum frequently coexists with postural deviations such as kyphosis or rounded shoulders. These changes develop as compensatory mechanisms to conceal the chest prominence or due to muscular imbalance between anterior and posterior thoracic muscles. Chronic poor posture can exacerbate musculoskeletal discomfort and perpetuate deformity appearance, emphasizing the need for postural retraining in management.

Connective Tissue Disorders

Several systemic connective tissue disorders are associated with pectus carinatum. These include Marfan syndrome, Ehlers-Danlos syndrome, and Noonan syndrome. Patients with these conditions display features such as hypermobility, joint laxity, long limbs, and cardiovascular anomalies like aortic dilation or valvular defects. Recognizing these associations is essential for comprehensive evaluation and multidisciplinary care.

Cardiac Displacement or Compression

Although cardiac compression is more characteristic of pectus excavatum, significant anterior chest wall deformities may still influence cardiac positioning. In some instances, the heart may rotate or shift slightly within the thoracic cavity, which can be visualized through imaging studies. Rarely, patients may experience mild arrhythmias or palpitations related to this altered anatomy.

Psychosocial Consequences

Psychological distress remains one of the most prominent complications. Persistent self-consciousness about appearance can lead to anxiety, social avoidance, and reduced quality of life. Adolescents are particularly vulnerable to these effects, and psychosocial support should accompany physical treatment. Addressing emotional well-being is an integral part of long-term management.

Treatment and Management

Non-Surgical Management

Non-surgical treatment remains the first-line approach for most patients with flexible pectus carinatum, particularly those in the growth phase. The goal is to remodel the chest wall gradually using external pressure and supportive exercises. Successful outcomes depend on early diagnosis, skeletal immaturity, and patient adherence to prescribed therapy.

Bracing (Dynamic Compression Orthosis)

Dynamic compression bracing is the standard conservative therapy for pectus carinatum. The brace applies adjustable anterior-posterior pressure across the sternum, promoting gradual remodeling of the cartilage and bone. Treatment typically begins during adolescence when the chest wall is still pliable. Braces are custom-made to fit each patient and are adjusted periodically based on progress and comfort.

• Duration: Most patients wear the brace for 16–20 hours per day for 6–12 months, followed by a maintenance phase with reduced hours.
• Advantages: Non-invasive, effective in growing children, and avoids surgical risks.
• Challenges: Requires motivation, consistent usage, and careful skin care to prevent irritation or discomfort.

Regular clinical follow-up ensures appropriate adjustment of compression pressure and monitoring of skin integrity. Compliance and early intervention are key factors influencing success rates, which exceed 70–80% in properly selected patients.

Physiotherapy and Postural Exercises

Physiotherapy complements bracing by strengthening the thoracic musculature, improving flexibility, and correcting postural imbalances. Exercises targeting the pectoralis major, intercostal, and spinal muscles enhance chest wall mobility and respiratory efficiency. Breathing exercises, such as diaphragmatic breathing and inspiratory muscle training, may also help alleviate mild respiratory discomfort. Postural retraining reduces compensatory kyphosis and improves overall thoracic alignment.

Monitoring and Growth-Stage Management

During adolescence, the chest wall continues to remodel in response to growth. Regular evaluation every 3–6 months helps track deformity progression, treatment response, and brace adjustment. Once skeletal maturity is reached, the chest becomes less malleable, reducing the effectiveness of bracing. In such cases, surgical options may be considered for patients with persistent deformity or psychological distress.

Surgical Management

Surgery is reserved for patients with severe, rigid, or asymmetric deformities unresponsive to bracing. The aim is to restore normal chest wall contour and symmetry while minimizing complications. Two principal surgical approaches are used: the Ravitch procedure and the minimally invasive Abramson technique.

Indications for Surgery

• Failure or intolerance of orthotic treatment.
• Rigid chest wall deformities unresponsive to external compression.
• Significant psychosocial distress due to cosmetic deformity.
• Associated cardiopulmonary compromise (rare).

Ravitch Procedure

The Ravitch operation is an open surgical technique that involves resection of the overgrown costal cartilages and repositioning of the sternum into a normal alignment. A metal bar or support strut may be placed temporarily to maintain the corrected position during healing. This method allows precise correction of complex or asymmetric deformities but requires longer recovery and carries risks such as infection, bleeding, or scarring.

Minimally Invasive Repair (Modified Abramson Technique)

The Abramson technique, also known as the “reverse Nuss procedure,” is a less invasive option that uses a subcutaneous metal bar to apply anterior compression on the sternum. The bar is fixed laterally to the ribs and remains in place for 2–3 years before removal. This procedure avoids extensive cartilage resection and provides good cosmetic results with shorter hospitalization time. Postoperative discomfort is typically managed with analgesics, and patients return gradually to normal activities.

Postoperative Care and Recovery

Following surgical correction, patients are encouraged to maintain upright posture, avoid strenuous activity, and participate in physiotherapy. Regular follow-up appointments assess bar stability, wound healing, and respiratory function. Once the corrective bar is removed, recurrence is uncommon if adequate healing and chest wall remodeling have occurred. Long-term outcomes show significant improvements in body image and psychosocial well-being.

Prognosis and Long-Term Outcomes

Success Rates of Bracing and Surgery

Non-surgical bracing achieves excellent results in most patients when initiated during early adolescence, with deformity correction rates exceeding 75%. Compliance, age, and flexibility of the chest wall are major determinants of outcome. Surgical techniques such as the Ravitch or Abramson procedure provide durable correction with high patient satisfaction, especially in rigid or asymmetric cases.

Recurrence and Relapse Factors

Relapse can occur if bracing is discontinued prematurely or in individuals who experience significant growth after treatment. In surgical cases, recurrence may result from inadequate cartilage removal, incomplete correction, or structural regression during healing. Regular follow-up and adherence to post-treatment instructions are essential for maintaining long-term results.

Impact on Pulmonary and Cardiac Function

In most patients, pulmonary and cardiac function remain within normal limits both before and after correction. However, in severe deformities, surgery may slightly improve respiratory efficiency and exercise tolerance by optimizing thoracic mechanics. Long-term studies indicate that correction enhances overall functional capacity and reduces discomfort associated with chest tightness.

Psychosocial Outcomes

Psychological well-being significantly improves after successful correction of pectus carinatum. Enhanced body image and self-confidence contribute to better social interaction and emotional health. Adolescents, in particular, report reduced embarrassment and greater participation in physical and social activities. Psychosocial assessment should remain an integral component of evaluation both before and after treatment.

Prevention and Patient Education

Early Screening During Growth Spurts

Although pectus carinatum cannot always be prevented due to its genetic and developmental origins, early detection during growth years plays a crucial role in minimizing deformity progression. Routine screening by pediatricians or school health programs can help identify chest wall irregularities at an early stage. Detecting the condition before skeletal maturity allows for timely initiation of conservative management such as dynamic compression bracing, which is most effective in flexible deformities.

Parents should be encouraged to monitor their child’s posture and chest shape during puberty, as the deformity tends to become more prominent during rapid growth spurts. Awareness of family history is also important, since hereditary patterns are common and siblings may be at increased risk.

Importance of Postural Awareness

Proper posture can reduce the visual prominence of pectus carinatum and improve musculoskeletal balance. Educational interventions focusing on spinal alignment, shoulder retraction, and strengthening of thoracic and back muscles should be introduced early. Ergonomic sitting positions, posture correction exercises, and physiotherapy guidance can help maintain normal thoracic mechanics and prevent secondary complications like kyphosis or scapular protraction.

• Encouraging regular physical activity helps maintain thoracic flexibility and muscular symmetry.
• Breathing exercises can enhance lung expansion and support chest wall mobility.
• Physical education teachers and sports coaches should be informed about the condition to avoid unnecessary restriction of participation in activities.

Family Counseling and Genetic Considerations

Genetic counseling may be beneficial for families with a history of pectus carinatum or connective tissue disorders. Counselors can provide information about inheritance patterns, recurrence risks, and the availability of early interventions. Families should be educated that the condition, while visible, is generally benign and treatable with high success rates. Psychological reassurance and early involvement of the child in treatment decisions promote better cooperation and self-confidence.

Education on Treatment Compliance

Patient education regarding adherence to brace usage and exercise routines is essential. Clear explanations of the treatment duration, expected outcomes, and potential discomfort improve compliance. Demonstrating brace adjustment techniques and explaining the importance of follow-up visits fosters active patient participation. Adolescents, in particular, benefit from motivational counseling to maintain long-term adherence and achieve optimal correction.

Recent Advances and Research Directions

Innovations in Orthotic Design

Recent years have seen significant progress in the design and customization of bracing systems for pectus carinatum. Modern dynamic compression braces incorporate lightweight materials, adjustable pressure sensors, and ergonomic contours for improved comfort and aesthetic appeal. Some devices now use digital sensors that monitor applied pressure and treatment duration, allowing clinicians to fine-tune therapy in real time. These advancements have increased patient compliance and enhanced treatment outcomes.

3D Imaging and Surgical Planning

Three-dimensional imaging and computer-aided design have revolutionized preoperative assessment and brace fabrication. Using digital surface scans, clinicians can precisely measure chest wall geometry, simulate corrective pressure, and design patient-specific orthoses. In surgical cases, 3D models assist in planning cartilage resection, bar placement, and predicting postoperative results. This technology has reduced procedural complications and improved symmetry after correction.

Minimally Invasive and Hybrid Techniques

Ongoing research focuses on refining minimally invasive surgical options that combine mechanical compression with limited cartilage modification. Hybrid techniques offer shorter recovery time, reduced scarring, and improved cosmetic outcomes. Innovations in bioabsorbable materials and custom-fitted internal supports are being explored to minimize the need for metal implants and secondary surgeries.

Long-Term Studies on Quality of Life

Current research emphasizes the long-term psychosocial and functional benefits of both conservative and surgical treatments. Studies show that successful correction leads to significant improvements in self-esteem, participation in social activities, and physical confidence. Future investigations aim to develop standardized outcome measures that integrate aesthetic, physiological, and psychological factors to better assess overall quality of life in pectus carinatum patients.

Future Perspectives

Emerging areas of research include genetic mapping of cartilage development pathways, biomaterials for cartilage regeneration, and artificial intelligence–based prediction models for treatment success. Continued interdisciplinary collaboration between thoracic surgeons, biomedical engineers, and geneticists will advance understanding and management of chest wall deformities. The ultimate goal is to provide less invasive, patient-centered, and personalized care with durable functional and cosmetic outcomes.

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