It has been said that Arnold Schwarzenegger has small quads compared to modern bodybuilders. However, just the opposite may be true. When people say “quads” often they are referring to the whole thigh. What you’re actually seeing in modern bodybuilders is added development of the adductor muscles of the inner thigh. That’s the area that chafes together if you’ve got fat thighs. The other area that is more developed is the vastus lateralis which is the outer quadriceps muscle. This is the area that bows out on the sides if developed way beyond your bone structure and forces bodybuilders to wear clown pants to fit their legs in.
In the accompanying photo, look at the vastus medialis, the tear drop shaped quadriceps muscle of the inner thigh. Name one bodybuilder who who has greater length in that muscle. You know that longer muscle bellies are generally a good thing. Longer calves generally look better than shorter high calves. Longer biceps generally look better than biceps with a big tendonous gap between the biceps and the forearm. The same is true for quads. Some bodybuilders have short quad muscles. Some bodybuilders have gnarled vastus medialis that look like commas instead of tear drops. The same thing goes for the rectus femoris. Schwarzenegger’s rectus femoris are extremely detailed and are very three dimensional all the way to the top of the legs.
In summation, look at the photo below. Don’t laugh but a lot of bodybuilders today would say that the guy on the left has better quads. Quadriceps are the one muscle group that most bodybuilders can’t wrap their minds around aesthetically and end up saying someone who has overdeveloped ridiculously structured thighs has great quads.