Rodney

Just to double-check, I got down on the floor and did a few standard push-ups, and yep: the strain is on the upper pecs, shoulders, and a bit on the triceps. So no, probably not a good overall chest-building exercise.

If you're interested in the lower chest specifically, decline bench bench target mainly that area. But any good general pec exercise would probably help, because they would involve all heads of the muscle to some degree. Dumbbell flys or machine flys would be a very good isolation exercise, but a good old fashioned bench press should help, too.

If bench presses weren't developing the central and lower pecs for you, you might have been holding the bar too far up your torso, so that it descended toward the neck or clavicle area. I was trained to bring the bar down right at the bottom of the pecs, to involve all the pectorals more fully.

If you're not into getting back with weights, you can modify your pushups to make them more pec-friendly: Instead of placing your hands out to either side of your torso, place them in a narrow stance, so that both are mostly underneath your torso when you do the exercise -- 8 to 12 inches apart. And go slow on the negative/downward portion of the rep. It's hard! And a little harder on the wrists, too. But it'll do a better job for your pecs than a standard pushup.