The Haller index, created in 1987 by J. Alex Haller, S. S. Kramer, and S. A. Lietman, is a mathematical relationship that exists in a human

chest The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...

section observed with a

CT scan A computed tomography scan (CT scan; formerly called computed axial tomography scan or 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 ...

. It is defined as the

ratio In mathematics, a ratio shows how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six (that is, 8:6, which is equivalent to the ...

of the transverse diameter (the horizontal distance of the inside of the

ribcage The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels. The sternum, together known as the thoracic cage, is a semi- ...

) and the anteroposterior diameter (the shortest distance between the

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...

and

sternum The sternum 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 blood vessels from injury. Sh ...

). :

\ HI = \frac

where: : HI is the Haller Index : ''distance 1'' is the distance of the inside ribcage (at the level of maximum deformity or at the lower third of the sternum) : ''distance 2'' is the distance between the sternal notch and vertebrae. More recent studies show that simple

chest x-ray A chest radiograph, called a chest X-ray (CXR), or chest film, is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common film taken in med ...

s are just as effective as CT scans for calculating the Haller index and recommend replacing CT scans with CXR to reduce radiation exposure in all but gross deformities. A normal Haller index should be about 2.5. Chest wall deformities such as

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 pubert ...

can cause the sternum to invert, thus increasing the index. In severe asymmetric cases, where the sternum dips below the level of the vertebra, the index can be a negative value.

Sources

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See also

Sources