The ribs are divided into seven pairs of true ribs, three pairs of false ribs, and two pairs of floating ribs, as the following outline will show:
- Ribs
- 7 true
- 3 false
- 2 floating
- —
- 12 pairs in all.
The true ribs are connected behind to the spine and in front to the sternum.
The false ribs are connected behind to the spine, but are called false because they are not attached directly to the sternum, but indirectly, the cartilages attaching to the cartilage of the rib next above.
The floating ribs are so named because they are only attached at one place, which is the spine and are loose or float in front.
The Bones of the Upper Extremities.
—The Shoulder girdle consists of the clavicle and scapula.
The Clavicle.—The clavicle or key bone, so-called because of its supposed resemblance to the key used by the Romans, forms the anterior portion of the shoulder girdle. It is often commonly called the collar bone.
The Scapula.—The scapula comes from a Greek word meaning “a spade.” It forms the back part of the shoulder girdle.
The arm is that portion of the upper extremity which is situated between the shoulder and the elbow.