The 13 ribs of the dog's chest wrap around the heart and lungs. Since these organs influence the animal's speed and stamina, chest size can be an indication of these traits. All dogs have 27 bones from the skull to the point where the tail begins. The number of tailbones, however, and therefore the length of the tail, varies from breed to breed. The body may be covered with straight or with wavy hair.
Hair shafts emerge from tiny follicles in the skin.
The shafts are connected to tiny muscles that cause the dog's hair to stand up, or bristle, when they contract. Special sensory hairs called whiskers are near the nose, but their usefulness is doubtful because a dog rarely relies on the sense of touch. The front legs and back legs of a dog are also called the forelimbs and hind limbs. A dog uses its legs for movement, for scratching, and, in some breeds, for digging. Each of the forelimbs is connected to the body by a long, narrow scapula, or shoulder blade.