Pectus carinatum, also called pigeon chest or pidgon breast, is a malformation of the chest characterized by a protrusion of the

sternum The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major bl ...

and

ribs The rib cage or thoracic cage is an endoskeletal enclosure in the thorax of most vertebrates that comprises the ribs, vertebral column and sternum, which protect the vital organs of the thoracic cavity, such as the heart, lungs and great vessels ...

. It is distinct from the related malformation

pectus excavatum Pectus excavatum is a structural deformity of the anterior thoracic wall in which the sternum and rib cage are shaped abnormally. This produces a caved-in or sunken appearance of the chest. It can either be present at birth or develop after puber ...

. Pectus carinatum has an estimated prevalence of approximately 1 in 1,000 to 1,500 live births, though specific figures vary geographically. It is generally less common than pectus excavatum. The condition is more frequently observed in males, with a male-to-female ratio ranging from 4:1 to 7:1. It typically becomes more noticeable during periods of rapid growth, such as early adolescence.

Signs and symptoms

People with pectus carinatum usually develop normal hearts and lungs, but the malformation may prevent these from functioning optimally. In moderate to severe cases of pectus carinatum, the chest wall is rigidly held outwardly. Thus, respirations are inefficient, and the individual needs to use the accessory muscles for respiration, rather than normal chest muscles, during strenuous exercise. This negatively affects gas exchange and causes a decrease in stamina. Children with pectus malformations often tire sooner than their peers due to shortness of breath and fatigue. Commonly concurrent is mild to moderate

asthma Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...

. Some children with pectus carinatum also have

scoliosis Scoliosis (: scolioses) is a condition in which a person's Vertebral column, spine has an irregular curve in the coronal plane. The curve is usually S- or C-shaped over three dimensions. In some, the degree of curve is stable, while in others ...

(i.e., curvature of the spine). Some have

mitral valve prolapse Mitral valve prolapse (MVP) is a valvular heart disease characterized by the displacement of an abnormally thickened mitral valve leaflet into the atria of the heart, left atrium during Systole (medicine), systole. It is the primary form of myxom ...

, a condition in which the heart mitral valve functions abnormally. Connective tissue disorders involving structural abnormalities of the major blood vessels and heart valves are also seen. Although rarely seen, some children have other connective tissue disorders, including arthritis, visual impairment, and healing impairment. Apart from the possible physiologic consequences, pectus malformations can have a significant psychological impact. A less common variant of pectus carinatum is ''pectus arcuatum'' (also called type 2 pectus excavatum, chondromanubrial malformation or Currarino–Silverman syndrome or pouter pigeon malformation), which produces a manubrial and upper sternal protrusion, particularly also at the

sternal angle The sternal angle (also known as the angle of Lewis, angle of Louis, angle of Ludovic, or manubriosternal junction) is the projecting angle formed between the manubrium and body of a sternum at their junction at the manubriosternal joint. The ster ...

. Pectus arcuate is often confused with a combination of pectus carinatum and pectus excavatum, but in pectus arcuate a protrusion of the costal cartilages characterizes the visual appearance and there is no depression of the sternum.

Causes

Pectus carinatum is an overgrowth of

costal cartilage Costal cartilage, also known as rib cartilage, are bars of hyaline cartilage that serve to prolong the ribs forward and contribute to the elasticity of the walls of the thorax. Costal cartilage is only found at the anterior ends of the ribs, pr ...

, causing the sternum to protrude forward. It primarily occurs among four patient groups, and males are more frequently affected than females. Most commonly, pectus carinatum develops in 11-to-14-year-old pubertal males undergoing a

growth spurt Human height or stature is the distance from the bottom of the feet to the top of the head in a human body, standing erect. It is measured using a stadiometer, in centimetres when using the metric system or SI system, or feet and inches when u ...

. Some parents report that their child's pectus carinatum seemingly popped up overnight. The second most common is the presence of pectus carinatum at or shortly after birth. The condition may be evident in newborns as a rounded anterior chest wall. The outward sternal protrusion becomes more pronounced as the child reaches age 2 or 3. Pectus carinatum can also be caused by

vitamin D deficiency Vitamin D deficiency or hypovitaminosis D is a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate exposure to sunlight, particularly sunlight with adequate ultraviolet B rays (UVB). Vitamin D def ...

in children (

Rickets Rickets, scientific nomenclature: rachitis (from Greek , meaning 'in or of the spine'), is a condition that results in weak or soft bones in children and may have either dietary deficiency or genetic causes. Symptoms include bowed legs, stun ...

) due to deposition of unmineralized

osteoid In histology, osteoid is the unmineralized, organic portion of the bone matrix that forms prior to the maturation of bone tissue. Osteoblasts begin the process of forming bone tissue by secreting the osteoid as several specific proteins. The os ...

. The least common is a pectus carinatum malformation following open-heart surgery or in children with poorly controlled bronchial

. Pectus carinatum is generally a solitary, non-syndromic abnormality. However, the condition may be present in association with other syndromes:

Turner syndrome Turner syndrome (TS), commonly known as 45,X, or 45,X0,Also written as 45,XO. is a chromosomal disorder in which cells of females have only one X chromosome instead of two, or are partially missing an X chromosome (sex chromosome monosomy) lea ...

Noonan syndrome Noonan syndrome (NS) is a genetic disorder that may present with mildly unusual facial features, short height, congenital heart disease, bleeding problems, and skeletal malformations. Facial features include widely spaced eyes, light-colored ...

Loeys–Dietz syndrome Loeys–Dietz syndrome (LDS) is an autosomal dominant genetic connective tissue disorder. It has features similar to Marfan syndrome and Ehlers–Danlos syndrome. The disorder is marked by aneurysms in the aorta, often in children, and the aorta m ...

Marfan syndrome Marfan syndrome (MFS) is a multi-systemic genetic disorder that affects the connective tissue. Those with the condition tend to be tall and thin, with dolichostenomelia, long arms, legs, Arachnodactyly, fingers, and toes. They also typically ha ...

Ehlers–Danlos syndrome Ehlers–Danlos syndromes (EDS) is a group of 14 genetic connective-tissue disorders. Symptoms often include loose joints, joint pain, stretchy velvety skin, and abnormal scar formation. These may be noticed at birth or in early childhood. Co ...

Morquio syndrome Morquio syndrome, also known as mucopolysaccharidosis type IV (MPS IV), is a rare metabolic disorder in which the body cannot process certain types of sugar molecules called glycosaminoglycans (AKA GAGs, or mucopolysaccharides). In Morquio syndro ...

trisomy 18 Trisomy 18, also known as Edwards syndrome, is a genetic disorder caused by the presence of a third copy of all or part of chromosome 18. Many parts of the body are affected. Babies are often born small and have heart defects. Other features in ...

trisomy 21 A trisomy is a type of polysomy in which there are three instances of a particular chromosome, instead of the normal two. A trisomy is a type of aneuploidy (an abnormal number of chromosomes). Description and causes Most organisms that repro ...

homocystinuria Homocystinuria (HCU) is an inherited disorder of the metabolism of the amino acid methionine due to a deficiency of cystathionine beta synthase or methionine synthase. It is an inherited autosomal recessive trait, which means a child needs to ...

osteogenesis imperfecta Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that bone fracture, break easily. The range of symptoms—on the skeleton as well as on the body's other Or ...

multiple lentigines syndrome Multiple may refer to: Economics *Multiple finance, a method used to analyze stock prices *Multiples of the price-to-earnings ratio *Chain stores, are also referred to as 'Multiples' *Box office multiple, the ratio of a film's total gross to tha ...

(LEOPARD syndrome),

Sly syndrome Sly syndrome, also called mucopolysaccharidosis type VII (MPS-VII), is an autosomal recessive lysosomal storage disease caused by a deficiency of the enzyme β-glucuronidase. This enzyme is responsible for breaking down large sugar molecules cal ...

(

mucopolysaccharidosis Mucopolysaccharidoses are a group of metabolic disorders caused by the absence or malfunctioning of lysosomal enzymes needed to break down molecules called glycosaminoglycans (GAGs). These long chains of sugar carbohydrates occur within the cel ...

type VII), and

Diagnosis

The pectus carinatum can be easily diagnosed by certain tests like a

CT scan A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

(2D and 3D). It may then be found that the rib cage is in a normal structure. The diagnosis of pectus carinatum is primarily based on a clinical physical examination. This chest wall deformity is visually characterized by an anterior protrusion of the sternum and ribs, often giving the chest a distinct "keel chest" or "pigeon breast" appearance. The "typical chondrogladiolar pectus carinatum" refers to the common presentation involving the lower and middle sternum.

Treatment

External bracing technique

Particularly in growing adolescents with flexible chest walls, non-surgical management is the first-line treatment. This primarily involves external bracing. The brace applies continuous, external pressure to the prominent areas of the chest, gradually reshaping the cartilages. Treatment success depends on the patient's age (younger patients with more flexible cartilage respond better), consistent brace wear (typically 12–23 hours per day), and the severity of the deformity. The duration of bracing usually ranges from 6 months to 2 years, often continuing until skeletal maturity. Regular follow-up with the bracing specialist is crucial to monitor progress and adjust the brace as needed. One notable system used in non-surgical management is the Dynamic Compression System (DCS) or the Dynamic Compressor System (FMF System), the FMF System has treated over 20,000 patients globally. This system utilizes a custom-made aluminum brace with a pressure measurement mechanism to ensure effective and safe correction. Studies have shown the FMF Dynamic Compression System to be an efficient, non-invasive treatment with low morbidity for typical chondrogladiolar pectus carinatum. For instance, a study involving 104 patients under 18 years old reported a positive qualitative assessment in 95.5% of cases, with an average correction time of 8.8 months and maintenance time of 8 months. Another study involving 208 patients highlighted the system's effectiveness and its ability to minimize complications like skin lesions or poor results through precise pressure measurement. Willingness to wear the brace as required is essential for the success of this treatment approach. The brace works in much the same way as

orthodontic Orthodontics (also referred to as orthodontia) is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, as well as misaligned bite patterns. It may also address the modificati ...

s (braces that correct the alignment of teeth). The brace consists of front and back compression plates anchored to aluminum bars. These bars are bound together by a tightening mechanism, which varies from brace to brace. This device is easily hidden under clothing and must be worn for 14 to 24 hours daily. Bracing is becoming more popular over surgery for pectus carinatum, mostly because it eliminates the risks accompanying it. The prescribing of bracing as a treatment for pectus carinatum has 'trickled down' from both pediatric and thoracic surgeons to the family physician and pediatricians again due to its lower risks and well-documented very high successful results. The pectus carinatum guideline of 2012 of the

American Pediatric Surgical Association The American Pediatric Surgical Association is an American professional organization dedicated to pediatric surgery. It was established in 1970 and had over 1,200 members as of 2015. Its official journal is the '' Journal of Pediatric Surgery''. ...

has stated: "As reconstructive therapy for the compliant pectus arinatummalformation, nonoperative compressive orthotic bracing is usually an appropriate first line of therapy as it does not preclude the operative option. For appropriate candidates, orthotic bracing of chest wall malformations can reasonably be expected to prevent the worsening of the malformation and often results in a lasting correction of the malformation. Orthotic bracing is often successful in prepubertal children whose chest wall is compliant. Expert opinion suggests that the noncompliant chest wall malformation or significant asymmetry of the pectus carinatum malformation caused by a concomitant excavatum-type malformation may not respond to orthotic bracing." Regular supervision during the bracing period is required for optimal results. Adjustments may be needed to the brace as the child grows and the pectus improves. Studies have demonstrated high effectiveness rates for non-surgical dynamic compression. Patient compliance is a critical factor for successful bracing outcomes. Research indicates that factors such as family support significantly contribute to brace treatment success. Novel wireless, real-time monitoring systems are being developed to address and improve patient adherence.

Surgical

For patients with severe pectus carinatum, surgery may be necessary. However, bracing could and may still be the first line of treatment. Some severe cases treated with bracing may result in enough improvement that the patient is happy with the outcome and may not want surgery afterward. Surgery would be the next step if bracing should fail for whatever reason. The two most common procedures are the Ravitch technique and the Reverse Nuss procedure. A modified Ravitch technique uses bioabsorbable material and postoperative bracing, and in some cases a diced rib cartilage graft technique. The Nuss was developed by Donald Nuss at the Children's Hospital of the King's Daughters in Norfolk, Va. The Nuss is primarily used for Pectus Excavatum but has recently been revised in some PC cases, mainly when the malformation is symmetrical.

Prognosis

Pectus malformations usually become more severe during adolescent growth and may worsen throughout adulthood. The secondary effects, such as scoliosis and cardiovascular and pulmonary conditions, may worsen with advancing age. Most insurance companies no longer consider chest wall malformations like pectus carinatum to be purely cosmetic conditions. While the psychological impact of any malformation is real and must be addressed, the physiological concerns must take precedence. The possibility of lifelong cardiopulmonary difficulties is serious enough to warrant a visit to a thoracic surgeon.

Epidemiology

Pectus malformations are rare; about 1 in 400 people have a pectus disorder. Pectus carinatum is rarer than

, another pectus disorder, occurring in only about 20% of people with pectus malformations. About four out of five patients are

male Male (Planet symbols, symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or Egg cell, ovum, in the process of fertilisation. A male organism cannot sexual repro ...

Citations

References

Sources

External links

{{Congenital malformations and deformations of musculoskeletal system Congenital disorders of musculoskeletal system