karotisbulbus

Karotisbulbus, or carotid bulb, is the bulbous expansion at the proximal portion of the internal carotid artery near the bifurcation of the common carotid artery into the internal and external carotid arteries. It represents the widened segment that marks the beginning of the internal carotid artery and is a common site for atheromatous plaque formation, which can narrow the lumen and increase the risk of cerebrovascular events.

Anatomy and relations: The common carotid artery ascends in the neck and divides into internal and external branches at roughly the level of the upper border of the thyroid cartilage. The carotid bulb is the dilation immediately proximal to the origin of the internal carotid artery. The carotid sinus, a nearby dilation that contains baroreceptors involved in blood pressure regulation, lies at the bifurcation region but is functionally distinct from the bulb.

Clinical significance: The carotid bulb is frequently involved in atherosclerotic disease, leading to carotid stenosis. Stenosis in this region can be evaluated with duplex ultrasonography, CT angiography, or MR angiography. Clinically significant stenosis raises the risk of ischemic stroke and may be managed with medical therapy or procedures such as carotid endarterectomy or carotid stenting, depending on symptoms and overall risk.

Notes: Terminology can vary in the literature. Some sources describe the bulb as the dilation near the bifurcation, while the carotid sinus refers to the dilation at the origin of the internal carotid with sensory (baroreceptor) function. The two structures are anatomically related but represent different concepts.