The thickness of the manubrium, the width and thickness of the body of the sternum at the level of second intercostal space as well as the thickness of the spongiosa and outer and inner compact layers have been measured in 67 human cadavers. Consequently, it is recommended that sternal puncture be made at the level of the second intercostal space in the adult and at the manubrium in children. Depth of puncture should not exceed 4 mm. Sternal puncture can thereby be done with greater confidence of avoiding penetration of the sternum, a potentially serious complication.