RT Journal A1 Hummel EP T1 EMbolism following knee-chest position post partum JF Journal of the American Medical Association JO Journal of the American Medical Association YR 1939 FD September 23 VO 113 IS 13 SP 1243 OP 1243 DO 10.1001/jama.1939.02800380061025 UL http://dx.doi.org/10.1001/jama.1939.02800380061025 AB To the Editor:—  The article in The Journal August 19 on this subject leaves many questions of doubt as to whether the emboli of air were due to air sucked in at the time that the knee-chest posture was assumed.The explanation of the modus operandi of the air getting into the vessels is far from convincing when the condition of the uterine muscle and its interior and the question of physics are considered.The vagina is a membranous pouch which may be expanded with air with the subject in the knee-chest posture by suction exerted when the abdominal viscera drop toward the chest. The uterus is a heavy, thick walled muscular organ the tendency of which is to contract rather than dilate, and it is questionable whether the weight of the viscera would be sufficient to cause dilatation enough to fill the uterus with air, as it has a