"The Strongest and Longest Bone The femur contains blood marrow and along with the pelvis, produces red blood cells. This is why femur fractures can lead to severe blood loss and low blood pressure. EMTs often use mast pants (pants that inflate and put pressure on the legs) to prevent hypotension. Our femur earrings, unlike real femurs, don’t break easily at all. They’re a great gift for: EMTs, orthopedic surgeons, soccer players, starry-eyed pre-med students."