The corpora cavernosa are two cylindrical structures located in the penis. They run along the length of the organ and are responsible for its ability to become erect. When a man is sexually aroused, blood flows into these structures, causing them to expand and harden, leading to an erection. In addition to their role in sexual function, the corpora cavernosa also play a part in the overall anatomy of the penis. They are surrounded by a tough fibrous sheath called the tunica albuginea, which helps maintain the rigidity during an erection.