Pectus Excavatum Terminology

Heath professionals use the Chin classification and the Haller index to describe the different types of  Pectus Excavatum.

Chin classification of Pectus Excavatum

The Chin classification categorizes the different types of Pectus Excavatum according to their morphological characteristics.

  • CHIN 1: the malformation is symmetrical, deep and focused on the sternum.

Dessin anatomique - Pectus Excavatum Type I  Scan - Pectus Excavatum Type I   Pectus Excavatum Type I - Vue 3DPectus Excavatum Type I - Femme Pectus Excavatum Type I - Homme


  • CHIN 2: the malformation is symmetrical, shallower and extends to the pectoral regions.

Dessin anatomique - Pectus Excavatum Type II Scan - Pectus Excavatum Type II Pectus Excavatum Type II - Vue 3DPectus Excavatum Type II - FemmePectus Excavatum Type II - Homme


  • CHIN 3: the malformation is asymmetrical and extends to the pectoral regions. The deviation is most often on the right side.

Dessin anatomique - Pectus Excavatum Type III Scan - Pectus Excavatum Type III Pectus Excavatum Type III - Vue 3D Pectus Excavatum Type III - FemmePectus Excavatum Type III - Homme






Other types of Pectus Excavatum

There are other types of Pectus Excavatum not defined in the Chin Classification.

  •  Pectus Arcuatum: Congenital chest malformation that lifts the upper part of the sternum transversely. An arch is formed by the protrusion of the upper part of the sternum and the adjacent costal cartilages, which induces a medial trough called the sternal trough.

Pectus Arcuatum - Vue 3DPectus Arcuatum - FemmePectus Arcuatum - Homme







  • Mixed Pectus Excavatum: There are Pectus Excavatum mixing several types of Chin's classification. For example, the right side with a Chin 1 and the left side with a Chin 3 because it is more extended on the pectoral region. 


Haller index of Pectus Excavatum

Indice de Haller- Pectus excavatum


To identify the depth of a Pectus Excavatum depression, the Haller index is calculated from a patient's CT-scan. This index divides the thorax width (in red) by the vertebro-xiphoïdal distance: the space that separates the dorsal vertebrae, from the deepest point of the thorax (in green).

The Haller index allows measurement of the defect and Pectus Excavatum depth especially in women where the deformation is hard to evaluate because of the breast volume. The higher the Haller index, the deeper the Pectus Excavatum.





Haller JA, Kramer SS, Lietman A. Use of CT scans in selection of patients for pectus excavatum surgery: a preliminary report. Journal Pediatric Surgery 1987;22:904-6
Guyuron B, Michelow BJ, Willis L. Practical classification of chin deformities. Aesthetic Plast Surg. 1995 May-Jun;19(3):257-64.