Hilton's Law states that:

the blood vessels and nerves to a given joint must follow the same pathway through the joint.
a nerve innervating a joint must innervate only that joint.
a joint must not be supplied by the same nerve that innervates surrounding muscles.
a nerve innervating muscles that act across a joint must also supply sensory fibers to that joint.
a blood vessel supplying muscles that act across a joint must also supply branches to that joint.