A Rare Case with Absent Second Rib, Bifid Costal Cartilages and Bifid Xiphoid Process.

ABSTRACT

Thoracic cage is made up of twelve thoracic vertebrae, twelve pairs of ribs and costal cartilages (CC) and a sternum. Ribs articulate anteriorly with sternum through CC which are flattened bars of hyaline cartilage considered as unossified anterior part of embryonic cartilaginous ribs. Numerical and structural variations of ribs are well documented. In the present study, we observed both structural and numerical variations of thoracic cage, bilaterally. On both the sides, eleven pair of ribs were present, instead of seven, six true ribs were found and second rib with CC was absent. Second and third CC and third CC of right and third CC of left side were bifid. Cartilaginous bridges were present between various CC on both sides. In the midline xiphoid process was found to be bifid. These variations are of immense help to the physicians, surgeons and radiologists.