BCP 201 GD: Bones 5 I-L (Second Timers)

House roof trusses use nailing plates–ghosting plates–to hold them together. These plates hold the trusses together considerably better than nails do.

The keel of a bird is in the center of its chest. The flight muscles of the wings grow into it.

Which has the larger keel in relation to its body size?

Sailboats have large keels because it helps them negotiate tight turns.

The flat sternum that we have is easier to attach muscles strongly to than a “cliff-like” keel that many birds have.

Your pectoral muscles are connected to your sternum. A bird’s flight muscles are attached to its keel.

“Bone Cliffs” provide more surface area for muscle to attach. A taller, longer keel has more area to attach the huge flight muscles of some birds than a shorter keel.

The clavicle’s “bone cliff” of our shoulder blade gives the shoulder muscle greater surface area to attach to. The sternum of our chest has a “cliff” like the clavicle to attach the pectoral muscle to.

The pectoral muscle attaches to the clavicle in a wide band.

The supracoracoideus pulls the wing up with an interesting pulley system. It is the muscle which is on the outside of the pectoralis (pec) muscle of the bird.

The pectoralis muscle (pec muscle) attaches to the keel. It pulls the wing down with a powerful stroke. In the pictures of it in this article, this muscle is larger than the supracoracoideus muscle.

Flying birds have a sternum that is sometimes nearly equal in width and height. Ostriches don’t have a keeled sternum. Swimming birds like the penguin have a thin sternum. Walking birds have a long sternum.