Side view: There's always the eye as an aiming point, or right under the ear. The heart is low in the chest, and sorta just-behind the front leg. The heart is about fist-size. Since the vital areas for these aiming points are roughly centered in the head or body, any quartering shot needs to follow an imaginary line to that vital spot.
You can try for just below the top of the shoulder; this can break both the leg and the spine. A high heart-lung shot will have the animal running but bleeding out, massively, internally. They won't run far.
If a hog is coming toward you, don't go for a between-the-eyes shot because of the chance of a glancing, non-penetrating hit. Aim more toward the nose and let the slug go through the softer bone below the eyes and on into the body.
Whether squirrel, kitty-cat, deer, human or hog, mammalian organs are pretty much in the same relative position in the carcass. The primary difference is the density of the bone and the toughness of the hide.
Right now, we seem to have a surplus of both humans and hogs, but I'm told the former are out of season for ethical hunters in the U.S.--which sez sumpn for the State of the Nation.
, Art