Bruits arise from turbulent blood flow causing arterial wall vibrations that are audible at the body surface with the unassisted ear or with a stethoscope (diaphragm rather than bell, better for detecting higher frequency sounds). They are associated with stenotic vessels or fistulae where there is arteriovenous shunting of blood. Dependent on the clinical indication, various sites may be auscultated: eye for orbital bruit in carotico-cavernous fistula; head for bruit of AV fistula; but probably the most frequently auscultated region is the carotid bifurcation, high up under the angle of the jaw, in individuals thought to have had a transient ischemic attack or ischemic stroke. Examination for carotid bruits in asymptomatic individuals is probably best avoided, other than in the clinical trial setting, since the optimal management of asymptomatic carotid artery stenosis has yet to be defined.
Sandercock PAG, Kavvadia E. The carotid bruit. Practical Neurology
2002; 2: 221-224