13 April 2006

Tuesday Rib Cage Study

I went a little more in depth and studied the bones of the rib cage today. I learned that the spine has the "s" curve to it to support the different body parts attached to it. The top curve comes in under the head, then curves out to support the rib cage, the curves in again to support the pelvis. The number of vertabrae accordingly are 7, 12, and 5. The rib cage itself can be seen inside of four boxes. Each box being roughly the same side as your skull (minus the jaw). The sternum is half as tall as the rib cage. The clavicle on either side is the same length as each box (or the width of the ball of the head). There are twelve ribs but only ten connect to the sternum. There's a plane break in the rib cage in the front where the bone and cartilage meet. In the back, the plane break follows the curve of the scapula. The scapula too is as tall as one box and roughly half as wide. The cartilage at the bottom of the sternum is called the ensiform cartilage and if you draw a construction line horizontally across its end you'll find the wide point of the ribs cage. I'm not sure you can see everything. I need to learn to scan these pencils drawings in better...

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