Pectus Carinatum (Pigeon Chest) Pectus carinatum deformity is the protrusion of the chest wall forwards in a severe degree.It is seen less than pectus excavatum deformity;the ratio is 1:5.It is considered to be formed by the overgrowth of the cartilage ribs which forces the sternum forwards.It might be symetric and asymetric;also above or below the sternum.In addition mix deformities might be observed such as the depression of the cartilage ribs in one side ,protrusion in other side with the combination of sternal rotation might be examined.The most frequent form is the symetric protrusion of the sternal corpus with the inferior cartilage ribs.