• Clinical science



True aneurysms are an abnormal dilation of an artery due to a weakened vessel wall. By contrast, false aneurysms are external hematomas with a persistent communication to a leaking artery. Dissections are a separation of the arterial wall layers caused by blood entering the intima-media space after a tear in the internal layer occurred. Aneurysms are differentiated according to their location. This card discusses the etiology and clinical features of cerebral, external carotid, Ileofemoral, popliteal, and ventricular aneurysms. Symptoms generally depend on the location and size of the aneurysm. There are surgical and endovascular treatment options, the choice of which depends on the specific type of aneurysm and if symptoms or complications are present.

For more specific information on individual types of aneurysms, see the learning cards on thoracic aortic aneurysm, abdominal aortic aneurysm, aortic dissection, dissection of the carotid and the vertebral artery, and subarachnoid hemorrhage.


Aneurysm vs. dissection

True aneurysm False aneurysm (pseudoaneurysm) Arterial dissection
  • Abnormal dilation of an artery due to a weakened vessel wall
  • Leaking artery leads to a hematoma between the vessel and the surrounding tissue. A persistent communication between the vessel and the hematoma remains.
  • Separation of the arterial wall layers
Etiology/Risk factors
  • Usually trauma (e.g., deceleration injury, gunshot) or iatrogenic (e.g., after vascular puncture or cardiovascular surgery)
  • Perforation of the vascular wall causing bleeding into the surrounding tissue
  • Formation of an extravascular (pulsatile) hematoma
  • → Surrounding structures delimit the expansion of the hematoma
  • → Organization of the hematoma
  • → Formation of a false vascular wall and false aneurysm
  • Typical deceleration injury → contained aortic injury of the thoracic aorta (typical location: distal to the left subclavian artery)
  • Transverse tear in the arterial intima (“entry”)
  • → Blood enters the intima-media space (creates a false lumen)
  • Hematoma forms and propagates longitudinally downwards
  • → Rising pressure within the aortic wall and rupture, occlusion of branching vessels, and ischemia in the affected areas
Clinical features
  • See table of different types of aneurysm according to location below.
  • Painful and pulsatile mass at the site of trauma
  • Buzzing sensation
  • Bruit on auscultation

Types of aneurysm according to location

Location Etiology Clinical features
Thoracic aortic aneurysm (TAA)
Abdominal aortic aneurysm (AAA)
  • Commonly below the renal arteries, may be above the renal arteries
  • Usually asymptomatic
  • Pulsatile abdominal mass
  • Bruit on auscultation
Cerebral aneurysm
  • Depends on type of aneurysm (berry, fusiform, mycotic, traumatic, or microaneurysms)
Ventricular aneurysm
Popliteal aneurysm
Ileofemoral aneurysm
Carotid aneurysm


Cerebral aneurysm


Popliteal aneursym


Ileofemoral aneurysm


External carotid artery aneurysm


Ventricular aneurysm


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last updated 04/27/2020
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