DR. E. WALKER / SCIENCE PHOTO LIBRARY DR. E. WALKER / SCIENCE PHOTO LIBRARY
Aneurysm. Human spleen with aneurysm of the splenic artery. The aneurysm has been cut open to show the large blood clot inside. An aneurysm is an abnormal dilation (ballooning) of the blood vessel occurring where the vessel wall is weakened. Pressure of blood at this weakened region prompts the wall to distend, or forces blood through a fissure in the internal wall of the artery. Weakening of the blood vessel wall is often caused by atherosclerosis in which fatty plaques develop and coat the inner walls of arteries. An aneurysm may exert pressure on surrounding organs, or may rupture, sometimes causing fatal blood loss.
Model release not required. Property release not required.