Wistar in 1818 gives an account of a person in whom one side of the thorax was at rest while the other performed the movements of breathing in the usual manner.
In some cases we see fissure of the sternum, caused either by deficient union or absence of one of its constituent parts.

In the most exaggerated cases these fissures permit the exit of the heart, and as a general rule ectopies of the heart are thus caused.

Pavy has given a most remarkable case of sternal fissure in a young man of twenty-five, a native of Hamburg.

He exhibited himself in one medical clinic after another all over Europe, and was always viewed with the greatest interest.

In the median line, corresponding to the absence of sternum, was a longitudinal groove bounded on either side by a continuous hard ridge which articulated with the costal cartilages.