The front legs for a feline are very "rigid" compared to what people think of them. You would think that an animal as flexible as the cat would have a more freely placed front leg, but they are more like a stiff stick rather than something moldable.
When we see the bones underneath it becomes apparent as to why a cats leg looks the way it does. However its not just bones that shape their legs its the muscles too. Most of what we see on the outside is shaped by bones and muscles under the skin; which is flexible and abundant.
The hind leg are the cats main asset. They are jumping animals and their hind legs are what propel them forward, or up a tree, (Or after your feet in the middle of the night).
Cats hind legs are built strong and look powerful.
Compared to another four legged animal, such as the dog, the cats hind legs may seem a bit too short, but they are just right for the way the cat moves. Cats aren't built to run. They are built to stalk and when they do run it isn't for very long, usually just short quick bursts.
The most prominent feature on a cats hind leg is the way the hock or ankle is set. It is usually lower set than the knee, but should fall perpendicular to the knee.
Cats legs are a lot longer than you think, you just cant see how long. Hidden under all their muscles and fur they actually have very long legs. Especially the back legs. With these strong back legs cats can jump 5 times high as they are tall and can jump up to 7 times their tail length.
Canine chests are built differently to Feline chests. Canines tend to have a wide broad chest, this is because their ribcage is further up then that of a cats. If a cat is drawn with a wide chest it will look unbalanced and clumsy.
Differences from Canines
You can see here how different a cat is to a dog. Most people think that they are similar because they walk on 4 legs. But even that makes them completely different
Even though dogs are bigger animals their legs are much shorter that cats (in comparison to the size of their body). Dogs are built for running. Cats are built for pouncing. This shows in their skeletons
Their spine is more curved and much longer than that of a dogs. This helps the cat to be as flexible as it is. Even more so with the "rag doll" breeds of cats.
The tail of a cat is a lot longer than a dogs (in most cases) and this helps the cat with balance.The domestic cat is the only species able to hold its tail vertically while walking. You can tell a lot about a cats mood by observing the posture of its tail.