Adding onto to a couple of ideas from yesterday’s post, I’ll go a little deeper into a number of the body’s wonderful details of functional necessity. In general the conjunction of muscles and tendons moving bones is enough to accomplish most actions required of the body. But there are a few spots where muscle alone is not enough and the body provides assistance that takes on different forms.
The rectus abdominis is a muscle that spans the distance between the base of the rib cage and the pelvis. It functions to draw the rib cage and the pelvis towards each other. The distance between the pelvis and ribcage is actually too great for a single muscle to work effectively so there are tendons in between the string of muscles that makes up the six pack that I always like to point out is a ten pack. These tendons act to stabilize and increase the strength of this intrinsic abdominal muscle.
There are a number of pulley systems in the body. A pulley is a simple machine that provides a mechanical advantage in order to move an object with less force. Muscles and tendons act like the rope around a pulley in a number of places in the body. The inner and outer ankles bones are the pulley with the peroneal brevis and longus and both tibialis poster and anterior providing the rope, the quadriceps is the rope for the pulley of the knee as the psoas plays the rope to the hips pulley.
The IT band is connective tissue that runs along the outer leg because no muscle that long would be able to stabilize the knee the way it needs to when walking. Poor posture affects the IT band intensely because it is less forgiving than muscle and as a result it takes on more strain when the bones are misaligned.
Sesamoid bones embedded into tendons increase the power and leveraging ability in the muscles the tendons connect to. The kneecap is a sesamoid bone that provides more power to the quadriceps. And yesterday I wrote about the sesamoid bones of the feet.
I feel so lucky to do what I do because the body amazes me and keeps me on my toes as I try to figure out it magnificent workings.