There are three types of muscle in the human body. Cardiac muscle is found only in the heart. Striated muscle is voluntary and attached to our skeleton so that we can skip and dance. Smooth muscle is not voluntary, we have no conscious control over it. It is found in the walls of hollow viscera, airways, blood vessels, the iris and in hair follicles. There is no fourth category of muscle. If uterine smooth muscle was so different from other smooth muscle then it would be in a section of its own. If uterine smooth muscle was designed to cause pain when contracting, as many people believe, then it would be very different from the smooth muscle in your stomach. It is not.
I have read thorough Tortora and Grabowski's Principles of Anatomy and Physiology on muscle tissue and nowhere do they say that uterine smooth muscle is any different to smooth muscle in other parts of the body. In fact, I think they would turn in their penthouses if anyone suggested that their beautiful book had a major flaw, that of not recognising a fourth muscle group.
So, why do so many women today experience uterine smooth muscle contractions as painful when they go into labour?
See earlier posts:
- Why labour hurts.
- Why labour hurts 2
- Why labour hurts 3
- Why labour hurts 4
- Why labour hurts 5