Certain air sacs have evolved in multiple lineages of soaring birds, and it emerges that these probably function to reduce the force required from the major flight muscles as they hold the wings in ...

Your pectoralis major is a large and powerful chest muscle that’s shaped like a fan. It starts from two sections: your breastbone (sternum) and your collarbone (clavicle). The two sections come ...

The pectoralis major muscle is a large muscle in the upper chest, fanning across the chest from the shoulder to the breastbone. The two pectoralis major muscles, commonly referred to as the ‘pecs,’ ...