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Blood Flow and Erection Problems

The corpus cavernosa are the two spongy chambers along each side of the shaft of the penis. When you have an erection, the smooth muscle in these chambers relaxes, blood flows in through the penile arteries, and the chambers fill with blood and expand. The expanded chambers press against the veins that would normally drain blood from the penis, trapping the blood inside and making the penis erect.

After ejaculation or when you are no longer sexually aroused, the arteries narrow, the veins expand, and the blood drains out. The penis becomes limp.

Problems with the arteries and veins that supply blood to or return blood from the penis can cause erection problems. Vascular problems may be caused by:

  • Hardening of the arteries (atherosclerosis) in the penis. This may block blood flow into the arteries that fill the penis.
  • Side effects of medicines, such as some high blood pressure medicines.
  • Leaking of blood from the veins in the spongy chambers in the penis.
By Healthwise Staff
Primary Medical Reviewer William H. Blahd, Jr., MD, FACEP - Emergency Medicine
Specialist Medical Reviewer David Messenger, MD
Last Revised March 1, 2013

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