The penis is primarily composed of 3 main areas: one smaller chamber, the lower Corpus Spongisum that functions for urination and ejaculation, and two upper chambers, which together are called the Corpora Cavernosa, and are the areas where 90% of the blood is retained during an erection. Penis function, length and girth is limited to the maximum capacity of these two chambers.
To help your penis impotence problems you need to develop the Corpora Cavernosa. Like any tissue of the body, this can be achieved with proper targeted exercises or growth can be stimulated with specific products such as the ones I have used and speak about in this website.
Anatomy image of a male impotent penis, erectile dysfunction and my claims i can fix you