Which is the most common site of atherosclerotic plaque formation in the cerebral circulation causing ischemic stroke?

Explanation

## Most Common Site of Cerebral Atherosclerosis **Key Point:** The carotid bifurcation (where the common carotid artery divides into the internal and external carotid arteries) is the single most common site of atherosclerotic plaque formation in the cerebral circulation. ## Anatomical Predilection Sites for Atherosclerosis | Site | Frequency | Hemodynamic Basis | Clinical Significance | |------|-----------|-------------------|----------------------| | **Carotid bifurcation** | ~40–50% of large artery strokes | Low shear stress, turbulent flow at bifurcation | Accessible to carotid endarterectomy; duplex screening feasible | | MCA stem | ~20–25% | Proximal branching point, high flow | Often distal to carotid disease; harder to access surgically | | Vertebral artery origin | ~15–20% | Low shear at origin from subclavian | Often asymptomatic; risk of posterior circulation stroke | | Basilar artery | ~5–10% | Central location, high flow | Rare; associated with severe disability or death | **High-Yield:** The carotid bifurcation is vulnerable because: 1. **Hemodynamic:** Low wall shear stress and flow separation at the bifurcation promote atherosclerotic plaque deposition 2. **Anatomical:** The internal carotid artery is the direct continuation of the common carotid, and plaques preferentially form at the origin of the internal carotid 3. **Clinical:** Carotid bifurcation disease is the most common target for carotid endarterectomy (CEA) in stroke prevention ## Mnemonic: "CAVE" **Mnemonic: CAVE** — Common sites of Atherosclerosis in cerebral Vessels: - **C**arotid bifurcation (most common) - **A**nterior cerebral artery origin - **V**ertebral artery origin - **E**xtracranial carotid (proximal segments) ## Clinical Pearl **Clinical Pearl:** Carotid bifurcation disease is not only the most common site but also the most treatable. Symptomatic carotid stenosis ≥70% is an indication for carotid endarterectomy or carotid artery stenting, making identification of this lesion critical for secondary stroke prevention. [cite:Robbins 10e Ch 11]