EMBRYOLOGICALLY the sternum develops from two lateral cartilaginous bars. These unite at about the ninth month of intrauterine life. An arrest of development causes the appearance of a bifid sternum.1
All degrees of bifid sternum may occur, varying from an enlarged suprasternal notch to complete separation of the two halves of the sternum. Ectopia cordis may or may not accompany this defect in its more severe form.1-7 If the heart is not completely extrathoracic, repair can generally be carried out.
The occurrence of bifid sternum is a relatively infrequently reported anomaly. Only one case of a mild form of bifid sternum, reported in 1962,4 made up the experience of the Cincinnati Children's Hospital. There are other reports of bifid sternum in the literature.2,3,5-10 These were all associated with some degree of ectopia cordis. A syndrome of defects involving the abdominal wall, sternum, diaphragm, pericardium, and heart
HOFFMAN E. Surgical Correction of Bifid SternumUsing Marlex Mesh. Arch Surg. 1965;90(1):76-80. doi:10.1001/archsurg.1965.01320070078017