An important part of our work at Trinity PT is teaching clients how their body works so they can make good decisions to improve their health. Given that we specialize in all things related to movement we spend a lot of time teaching people what the various parts of the musculoskeletal system are, how they work and what they do. Things like bones, ligaments, tendons and muscles and fascia. So, over the course of 5 or 6 posts I am going to write a short bit about the major parts and tissues in our bodies that enable us to move.
Let’s start with bones.
These are the hard parts of the body, the beams, struts and girders we hang the rest of our frame on. No small part of their makeup is hard minerals (rocks) which make them sturdy and stiff. There Is some flexibility in bones but compared to other tissues they are pretty stiff. Bones provide support for things but also act as levers that the muscles pull on to move us through space. Where these levers meet, the fulcrum, is called a joint. A joint is a place not a thing, however, when most people talk about a joint they really mean all the tissues that keep the bones able to move correctly where they meet. (More about all the things around a joint in the next post.)
The body is very efficient and most things in us have multiple jobs, including bones. One of those jobs is to be the warehouse for multiple minerals such as magnesium, calcium, and phosphorus. These minerals are used by the muscles, nerves and various organs to do their jobs. Like any busy warehouse, materials are constantly coming in and out of the bones as they supplies arrive and requests for materials get fulfilled. Unlike most warehouses though, the bones also use what they are storing to make the hard parts of their own structure.
The bones are not completely solid, they have areas that are more porous, called spongy bone, (think of a dried loofah but harder) and hollow areas filled with fat and blood (marrow). Red blood cells to carry oxygen and white blood cells to fight infection are produced in these areas. In addition, the stem cells to create many other cells in the body are stored and started in the bones. It’s a sensible design because the cells and processes which are so critical to keeping us alive are stored in multiple, fortified places. If you damage or break a bone or lose a limb there are plenty of reserves to keep the blood and stem cell supply line running.
The key point about bone from a movement perspective is that they permit us to get our body into a huge number of shapes and positions to do work against gravity and move us through space much more efficiently than just being a soft mass like a slug. They also allow us to manipulate objects and apply an incredible amount of force to things so we can shape our environment. (How hard could you kick something if your leg was boneless?)
When bones break, they do a remarkable job of cleaning up the damage and mending back together if the pieces are kept close to each other. After six weeks or so they can get up to 90% of their strength back and go on to usually heal the site to be stronger than before.
So take a second and give your bones some credit, they are critical to keeping us alive and making us able to move through the world so well.
– By John Macy, PT