What is the strongest muscle in the body?

Did you guess tongue? You're wrong! Don't tell me you guessed heart because of the picture? Guess what you're still WRONG! So what in the world is the strongest muscle in the body? Well women, take a bow, because that award goes to the uterus.

Yes, you are reading that correctly! Many people believe that the tongue or jaw muscles are the strongest in the body when in fact its the contracting uterus that wins the battle. The uterus wall is made of a muscle called the myometrium. The wall of the uterus is very thin but has enough force to pull open the cervix and push a baby out! Maybe two or three if you're really lucky :)

So how does this muscle take the cake when compared to the ripped abs of the New York Fireman of the Month in the 2012 calendar? I saved you the trip. 

Well let me explain as simple as possible. The wall of the uterus pre-labor is about 2 cm thick when undilated. However as baby's head descends into the pelvic cavity and puts pressure on the cervix it signals the uterus to start the races. This signal will cause the uterus to begin to contract from the top (underneath the breasts at this stage) down to the cervix which will effectively start to thin out the cervix. This thinning of the cervix (as can be seen in the picture below)  is called effacement and this process will lead to dilation (opening) of the cervix and eventually deliver of baby. In addition, the actual size of the uterus will decrease throughout this process which will help push baby out of the womb as well.

So where's the amazing feat here? Well besides the fact that a baby is born, the uterus creates a TON of force. In fact according to Clinical Obstetrics there's about 7 kg or about 15 1/2 pounds of force on average created by the uterus during natural childbirth. This force is created by the slow and gradual contraction of the uterus that is associated with child birth that is not medically assisted. Now imagine this, before baby the uterus only weighed about 60 grams which is about the size of a large egg. I don't know about you, but I haven't seen any eggs walking around with a 15 1/2 pound punch so that is a feat in itself.

So now I'm sure you're all wondering what if it's not a natural child birth? Again I'm citing Clinical Obstetrics in their claim that oxytocin can stimulate the uterus to contract at 14 kg or more with some cases of up to 23 kg (50 pounds!) of force. 

So how does this compare with the tongue or the heart? The tongue weighs about 70 grams in males and 60 grams in females. In August of 2008 Thomas Blackthorne set a world record tongue lifting of 12.5kg after he hooked the weight onto a hook inserted through his tongue. Watch it here.

Wow those are some crazy numbers and crazy feats by the human body! So what's the purpose of my blog post today? To amaze you with the amazing things that your body can do when its healthy and functioning properly!