Also, forgot to add... There is Biceps Brachii, Brachialis, and Pronator Teres(correct?), and the only one that REALLY effects the bicep size, girth, etc is Biceps Brachii. Which has two heads. A...
Yeah... Same as with chest... You can hit Pectoralis Minor, or Major, depending on your grip, and neither will effect the inner-chest, nor will any widen you arms... other than triceps.