Also referred to as the beef 'Rump', the beef round primal cut basically consists of the back leg of the steer. Muscles from the round are fairly lean, but they're also tough because the leg and rump get a lot of exercise. Just like the sirloin primal is separated into two subprimals, top sirloin and bottom sirloin, beef round likewise consists of multiple subprimal cuts: the top round (inside round), bottom round (outside round), and the knuckle. The bottom round is where we get rump roast and eye of round.