Avian Muscle System - Page 1

A bird has some 175 different muscles controlling the movements of its wings, legs, feet, tongue, eyes, ears, neck, lungs, sound-producing organs, body wall and skin. Collectively, the muscles are concentrated near the bird's center of gravity.

Largest of all the muscles are the breast muscles, or pectorals. These muscles form the bulk of the fleshy mass in the breast and constitute about 15 to 20 percent of the bird's total body weight. They also provide the powerful downstroke of the wing and therefore bear most of the burden of supporting a bird in flight.

The supracoracoideus -- the muscle that raises the wing -- acts as the antagonist to the pectorals. This muscle is located below the pectoral muscles ventrally (on the front side). Together, these two muscles constitute about 25 to 35 percent of a bird's body weight. Besides the supracoracoideus there are numerous other small muscles of the wing that allow a bird to control flight.