the wonderful sacrum...

I started this post as a comment to Franks blog and then decided just to post it on my own blog as it was getting a little lengthy... Being a physio who has worked with clients who are pregnant and having taught part of antenatal classes i just couldn't help myself... sorry.

So I'd love to know exactly what Franks childbirth educator said about the wonderful sacrum.

Here goes the anatomy lesson. The spine is divided into different sections - Cervical (basically the neck), Thoracic (ribs attach to these 12 vertebrae), Lumbar (low back), Sacrum (base of the spine) and coccyx (tailbone). The Sacrum attaches on each side to the ilium, or pelvis. You can work out where this is by checking for the two dimples at the top of your butt.These two joints are called your sacroiliac joints (SIJ). The pelvis joins again at the front which is called the pubic symphysis joint. These three joints are pretty much the strongest joints in your body - have to be really!

As far as I'm aware, it is actually the coccyx (tailbone) that does most of the flexing and moving during birth. So by adopting different positions (I can hear Frank giggling ;o) the baby passes through the pelvis more easily. The SI Joints and pubic symphysis joints are softened during pregnancy by the hormone relaxin. This allows for the pelvis itself to stretch and give a little to assist with allowing the babies head through the pelvic outlet. So although the sacrum is a big part of all of this, it isn't the main event (so to speak).

As a side issue, my main personal pregnancy issue with Isabella & Hannah has been as a result of those softened pelvic joints. Dysfunction with these joints can cause lots of pain with walking, rolling in bed, getting up out of chairs, wallking up stairs etc etc... and it can take a while to come right. I still can't go for a short run without suffering the consequences afterwards... thats 10mths later...