Like almost all mammals, cats possess seven cervical vertebrae. They have thirteen thoracic vertebrae (compared to twelve in humans), seven lumbar vertebrae (compared to five in humans), three sacral vertebrae like most mammals (humans have five because of their bipedal posture), and twenty-two or twenty-three caudal vertebrae (humans have three to five, fused into an internal coccyx). The extra lumbar and thoracic vertebrae account for the cat's enhanced spinal mobility and flexibility, compared to humans; the caudal vertebrae form the tail, used by the cat for counterbalance to the body during quick movements (Zoolab 2007).
Hello, guys. I am here.
Cats, like dogs, are digitigrades: They walk directly on their toes, the bones of their feet making up the lower part of the visible leg. Cats are capable of walking very precisely, because like all felines they directly register; that is, they place each hind paw (almost) directly in the print of the corresponding forepaw, minimizing noise and visible tracks. This also provides sure footing for their hind paws when they navigate rough terrain.
Unlike dogs and most mammals, cats walk by moving both legs on one side and then both legs on the other. Most mammals move legs on alternate sides in sequence. Cats share this unusual gait with camels, giraffes, some horses (pacers), and a few other mammals.
Like all members of family Felidae except the cheetah, cats have retractable claws. In their normal, relaxed position, the claws are sheathed with the skin and fur around the toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows the silent stalking of prey. Cats can extend their claws voluntarily on one or more paws at will. They may extend their claws in hunting or self-defense, climbing, "kneading," or for extra traction on soft surfaces. It is also possible to make a cooperative cat extend its claws by carefully pressing both the top and bottom of the paw. The curved claws may become entangled in carpet or thick fabric, which may cause injury if the cat is unable to free itself.
Most cats have five claws on their front paws, and four or five on their rear paws. Because of an ancient mutation, however, domestic cats are prone to polydactyly, and may have six or seven toes. The fifth front claw (the dewclaw) is in a more proximal position than those of the other claws. More proximally, there is a protrusion that appears to be a sixth "finger." This special feature of the front paws, on the inside of the wrists, is the carpal pad, also found on the paws of dogs. It has no function in normal walking, but is thought to be an anti-skidding device used while jumping.