Your clavicles, or collar bones, are beautiful bones on either side of your sternum or breast bone. They use their wonderful double curves to connect your arms to your torso and help form your shoulder girdle. When we talk about the shoulder girdle we are referring to both clavicles and both scapula. Each clavicle connects to your sternum on the left and right at the sternoclavicular joint. The sternoclavicular joint provides the only connection between your quite complex shoulder girdle and your axial skeleton.
Understanding how your clavicle is positioned and moves can greatly change your posture and your practice. These are the bridges from your arms to your center and are more articulate in movement than you might think.
Not sure where yours are? They are easy to trace. Place your right hand on the notch of your sternum and trace this curvy bone out towards your left shoulder.
There's a lot in a name for this bone! Clavicle comes from the latin word for clavicula which means "key" or "little key". Your clavicle turns like a key at the sternoclavicular joint in relationship to how you are using your arms and shoulders. Your shoulder girdle floats on your rib cage like a collar floats around your neck.
Interesting Facts to change the way you think about your collar bones:
1. We sometimes think of our collar bones as the top of our torso. In fact your first rib is above your collarbone.
2. The clavicle is the first bone to begin the ossification process in the fetus and one of the last to finish ossifying.
3. It is the only bone that runs horizontal in the body.
4. There are so many muscles, ligaments, and tendons that help make our shoulder girdle both articulate and stable. Here are some of the muscles you might know that attach directly on the clavicle: pectorals major, trapezius, sternocleidomastoid, deltoid, subclavius and sternohyoid!
5. Birds that fly often and are not primarily ground dwelling have particularly strong clavicles that are unified at the sternum into one bone. This creates a strong rebound up in the wings when flying and creates resistance in the flap down making the whole motion more effective. Other animals that rely on running fast have no collar bones at all!
** "Left clavicle - close-up - animation" by Anatomography - en:Anatomography (setting page of this image). Licensed under CC BY-SA 2.1 jp via Commons - https://commons.wikimedia.org/wiki/File:Left_clavicle_-_close-up_-_animation.gif#/media/File:Left_clavicle_-_close-up_-_animation.gif