The reason given in my book is that it i because it interferes with the secondary hemostasis..but i did not understand how that implies that bleeding from deeper organs is more common..


1 Answer 1


Skin is extraordinarily tough compared to much of our internal tissues; it has to be to protect us. To bleed, skin integrity must be breached, which usually involves sharp objects.

Think for a moment that most splenic or hepatic injuries (even complete ruptures) occur from blunt force trauma without breaking the overlying skin. For a more common example, if someone hits your thigh with a baseball bat, you will get a large bruise, maybe even a broken bone, but the skin will usually remain intact (if badly bruised) from blood vessel damage beneath and within the skin.

Many organs are delicate, and damage within them is not rare. Bleeding within/from some bodily organs is fairly common: runners bleed from their kidneys, and many, many people bleed from somewhere in their GI tract. High blood pressure may cause bleeding in the brain (a stroke) but it won't cause bleeding from the skin.

Just add to all the above the effect of anticoagulation (what heparin does.) I hope that explains things. If it doesn't, please leave a comment.

  • $\begingroup$ Thank you very much for the explanation. To clarify further, i wanted to know whether bleeding from deeper organs probably happens (normally) also due to pressure from surrounding tissues? $\endgroup$
    – Curious
    Dec 29, 2018 at 19:06
  • $\begingroup$ @Curious - Not necessarily pressure from surrounding tissues, no. Our bodies are well designed with things to minimize the effects of normal pressure. $\endgroup$ Dec 29, 2018 at 19:56
  • $\begingroup$ Ok so..why exactly does bleeding occur more from deeper organs or delicate structures? Why is it 'delicate'? $\endgroup$
    – Curious
    Dec 30, 2018 at 6:03
  • $\begingroup$ Tissues are more delicate than skin because they serve a different function than skin, which is protective. They need protection: the brain needs the skull, the lungs, heart, liver, pancreas and spleen need the rib cage. We have minor internal injuries all the time: we damage our liver, we erode a part of the lining of our GI tract, we weaken blood vessels or break small ones, etc. Internal tissue isn't tough, it's tissue. Muscle is probably an exception, and bone is pretty tough, but even most broken bones occur without skin being damaged. $\endgroup$ Dec 30, 2018 at 15:07
  • $\begingroup$ Skin is just built to be tough. I could go into histological reasons (what you'd see in a microscope) but that would be outside the range of this question. $\endgroup$ Dec 30, 2018 at 15:08

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