Embolisms are typically named after the blood vessels they are lodged in or the composition of the embolus itself (e.g., a blood clot). Some of the more common embolisms include:

• Cerebral embolism (intracranial embolism). One of the most common causes of a stroke. It occurs when an embolus (usually a blood clot) becomes lodged in an artery in the brain, blocking oxygen-rich blood from nourishing the portion of the brain beyond the blocked artery. Without adequate oxygen, that area of the brain suffers tissue damage or death, causing typical stroke symptoms such as speech impairment, one-sided paralysis, or problems with comprehension or vision (depending on which portion of the brain was damaged).
  
  
• Arterial embolism. Most commonly seen as a complication of heart disease. Atrial fibrillation may also be present. Frequently, there is more than one embolus. Recurrences are common even after successful treatment of previous embolisms. Arterial embolisms tend to become lodged at the fork of major arteries, with over 50 percent affecting blood vessels in the lower extremities.
  
  
• Venous embolism. Much less common than arterial embolisms. Venous embolisms can be caused by globules of fat or bone marrow. These globules usually occur after a bone fracture and are released from the fracture site of a long bone (such as an arm or leg bone). In rare cases, a venous embolism may be caused by a bubble of air that has entered the body through a central intravenous line (IV) or during certain brain operations such as a sitting craniotomy.
  
  
• Pulmonary embolism. An embolism (usually a blood clot from the pelvic veins or deep veins of the leg, a condition called deep vein thrombosis) that becomes lodged in the pulmonary artery in the chest. This blockage causes a true medical emergency because it obstructs the blood supply to the lungs. It is a commonly occurring embolism that affects approximately 600,000 Americans every year, and 10 percent of those embolisms result in death.
  
  
• Amniotic fluid embolism. A very rare, life-threatening embolism that can occur in late pregnancy. Amniotic fluid enters the uterine veins through a tear in the placental membranes and travels to the lungs, sometimes leading to sudden cardiac death.
  
  
• Leg or arm embolism. An embolism, usually a blood clot, which blocks one of the arteries that supplies blood to an arm or leg.
  
  
• Fat embolism. An embolism that may occur after a long bone has fractured, releasing fat or bone marrow globules from the fracture site into the bloodstream. The globules then travel to the lungs and become trapped in the pulmonary capillaries, resulting in the same life-threatening situation as a pulmonary embolism.
  
  
• Air embolism. Bubble(s) of air or other gases that enter the circulation and travel to the lungs, heart or brain. There, they block normal blood flow and cause life-threatening medical emergencies. Air embolisms are a leading cause of death in scuba diving accidents (a condition called “the bends”) and can also occur during surgeries involving the head and neck, as well as vaginal delivery or cesarean sections (“C-section”).
  
  
• Paradoxical embolism. The result of an embolus that has traveled from the veins to the arteries to the brain (where it blocks a cerebral artery), or any other systemic artery. The embolism is “paradoxical” (contrary to the usual) because normally blood cannot travel from a vein into an artery. The condition can occur when an embolus crosses from the right side of the heart to the left side through a hole in the septum (the muscular wall that separates the left and right sides of the heart). The hole is usually the result of an unrepaired congenital heart defect (e.g., patent foramen ovale, atrial septal defect, ventricular septal defect).
  
  
• Cholesterol embolism. A life-threatening complication that can arise spontaneously or from medical treatments designed to reduce or dissolve plaque in the arteries, such as balloon angioplasty. During these medical treatments, cholesterol crystals may be released from the plaque into the bloodstream. If the cholesterol crystals travel to the lower part of the body, they can obstruct a blood vessel and cause a cholesterol embolism. Such embolisms usually obstruct small arteries. Besides balloon angioplasty, cholesterol crystals can be released from plaque through the use of anticoagulants, other catheter-based procedures and a type of thrombolytic therapy that uses t-PA (tissue plasminogen activator).
  
  
• Therapeutic embolism (embolization). The deliberate creation of an embolus to obstruct a blood vessel in order to stop internal bleeding or to cut off the blood supply to a tumor. These man-made emboli can be made of many different materials, such as fibrin, metal coils, silicone balloons, wool or medicinal glue.