Types of Thorax: Definition, Structure and Deformities Associated with This Bone Part of Vertebrate Animals

This part of the body is located between the head and the midsection.

The vertebrate thorax contains the principal organs of respiration and circulation: such as the lungs, some air passages, the heart, and the largest blood vessels.

Below, it is bounded by the diaphragm, and the bony framework is lined with muscles, fat, and skin tissues such as skin.

Structure of the rib cage

The bony framework of the human thorax is made up of different elements:

  • The sternum is a long, flat bone located front and center.
  • The thoracic spine, located at the back, comprises twelve thoracic vertebrae, separated by the intervertebral discs.
  • The ribs (twenty-four), which are long, curved bones, run from the back to the front through the lateral aspect

Rib cage shape

The ribs start from the spine and are attached to the sternum thanks to the costal cartilage, except for the last two ribs at the bottom.

Called floating ribs, the latter are not attached to the sternum. These unions allow giving the structure in the form of a cage.

The intercostal spaces are eleven and separate the twelve ribs of a lateral face. These spaces consist of muscles, arteries, veins, and nerves.


The chest cavity contains several vital organs, including the heart and lungs. The diaphragm limits the base of the thoracic cavity.

Functions of the rib cage

Protective role of internal organs

The rib cage protects some vital organs, such as the heart and lungs, as well as other abdominal organs.

Role of mobility

Its constitution, partly cartilaginous, gives it a flexible structure to follow the movements of the spine.

Role in respiration

The flexible structure of the cage and the various joints give it great ranges of motion, participating in respiratory mechanics.

Various muscles of respiration also sit at the level of the rib cage.

Rib cage pathologies

Chest trauma

It corresponds to the affectation of the thoracic cavity by shock in the thorax.

The ribs, sternum, and thoracic spine can suffer various fractures.

This leads to respiratory complications with paradoxical breathing.


It refers to the pathology that affects the pleural cavity, the space between the lungs and the rib cage.

It is manifested by severe pain in the chest, sometimes associated with breathing difficulties.

Chest wall tumors

Primary or secondary tumors can develop in the bones or soft tissues.

Bone diseases

The rib cage can be the site of the development of bone diseases such as osteoporosis or ankylosing spondylitis.

Chest Types

The deformities of the chest wall determine the types of the chest, and the following types are observed:

Normal chest

In the normal thorax, there are three types according to their proportions:

  1. Aesthetic: the thorax is more prolonged and less comprehensive.
  2. Asthenic hypersthenic: the thorax is thinner, and the lungs are narrower and more prolonged.
  3. Hypersthenic: the thorax and abdomen are broader and deeper from front to back.

EL tórax embudo (pectus excavatum)

It is a deformity characterized by a cupping of the anterior wall of the thorax, in which excessive growth of the costal cartilage occurs in the sternum and can affect the heart and lungs.

It is a common anomaly (1/300 births) that predominates in males.

The so-called “Chin” classification qualitatively describes the different types of pectus excavatum.

This type of abnormality is also described by a radiological measurement index (computed tomography and magnetic resonance imaging), the Haller index or “severity index,” which is calculated by dividing the transverse diameter of the chest by its anteroposterior diameter.

The average value of the Haller index is 2.5.

Tórax carinado (breast keel)

In this type of deformity, the sternum is projected forward by the hypertrophied costal cartilages.

More rarely, these anomalies can be associated with mixed forms that associate the different types of deformation.

A more rare “tall” form or pectus arcuatum defined by the manubriosternal pons is also described.

There may be associations between these abnormalities and certain spinal (scoliosis) or vascular (Marfan syndrome) pathologies that, although rare, should be investigated during the preoperative evaluation using a chest CT scan and cardiac ultrasound.

Emphysematous chest

An emphysematous chest is characterized by having the circumference of the upper portion of the chest more significant than the lower portion.

It is observed that the sternum protrudes, and the diameter of the thorax is much larger than usual.

Most patients with the chronic obstructive pulmonary disease generally develop this type of chest.

Harrison’s chest

Harrison’s chest arises in patients with rickets or some other calcium-deficient disorder due to the traction of the diaphragm on weakened ribs.

Kyphotic chest

The kyphotic thorax is a consequence of suffering from dorsal kyphosis.

scoliotic chest

This occurs due to a deformity of the spine called scoliosis.

Origin and cause of deformities

These deformities are due to an overdevelopment of the cartilage between the ribs and the sternum.

This “primitive” anomaly can subsequently give rise to all possible variations: excavatum (projection of the sternum behind), carinatum (point of the sternum forward), and mixed forms, among others.

The deformities of the anterior chest wall thus form a heterogeneous group whose origin is unique: cartilage hypertrophy.

Each case is unique and must be analyzed to provide the most appropriate medical response according to the anomaly’s anatomical characteristics and psychological and functional impact.

Rib cage exams

Clinical examination

Diagnosis begins with a clinical examination to evaluate the symptoms and characteristics of the chest.

Imaging tests

Depending on the assumed pathology, additional tests such as radiography, ultrasound, CT scan, MRI, or scintigraphy may be performed.


Non-surgical treatment

Anomalies of the anterior chest wall are typical, often moderate, and many patients do not feel any discomfort. It is not necessarily helpful to consider intervention in these cases.

There is a non-invasive alternative to surgical treatment: a silicone suction hood, called a “vacuum hood.”

This method aims to gradually reduce chest deformation by regularly applying a “suction cup.”

There is also a non-invasive method of treating some pectus carinatum using the so-called “dynamic compression” system.

It is a bra that exerts constant “pressure” on the protrusion of the sternum.

Good results are obtained mainly in young patients whose chest is still flexible.

If this treatment is chosen, it should be implemented during consultation under medical supervision after purchasing the device.

A follow-up is necessary to judge the effectiveness of the treatment applied in the long course (more than six months) by the patient himself.

Surgical treatment

Some patients consider the cosmetic damage significant and have a real psychological impact.

This prejudice varies from one person to another and from one moment of life to another in the same person.

Body image can be perceived differently depending on age.

On the other hand, the impact of these abnormalities on breathing is exceptional.

Breathing difficulties, when they exist, could be related to a compression of the heart and an obstruction to the proper functioning of the diaphragm.

They can cause a limitation of activities, especially during exertion.