The chest is a part of the anatomy of humans and various other animals sometimes referred to as the thorax.
In humans, the portion of the chest protected by the ribcage is also called the thorax.
In insects and other creatures with an exoskeleton, the area corresponding to the chest is called the thorax.
In four legged mammals, the mammary glands and nipples are located closer to the back legs, and are therefore not part of the chest. Otherwise, the anatomy contains similar internal organs in different configurations.