Bruits and Hums of the Head and Neck

A bruit is an audible vascular sound associated with turbulent blood flow. Although usually heard with the stethoscope, such sounds may occasionally also be palpated as a thrill . In the head and neck, these auscultatory sounds may originate in the heart (cardiac valvular murmurs radiating to the neck), the cervical arteries (carotid artery bruits), the cervical veins (cervical venous hum), or arteriovenous (AV) connections (intracranial AV malformations). These sounds may be normal, innocent findings (i .e ., a venous hum in a child) or may point to underlying pathology (i.e ., a carotid artery bruit caused by atherosclerotic stenosis in an adult) . Head and neck bruits loom especially important today because physicians encounter arterial occlusive disease more frequently as a greater proportion of our population lives longer . What are the clinical circumstances where head and neck auscultation is indicated? Evaluation often begins with patient symptoms related to cardiovascular or neurologic disease. This involves a through, directed physical examination following pertinent historical information. Second, the necessity for head and neck auscultation may be part of repeated or sequential physical examinations directed by new data from subsequent history, physical examination, or laboratory information obtained later in the hospital course . Finally, auscultation of head and neck vascular sounds may be part of a routine, complete (comprehensive) physical examination, especially in subsets of patients at risk for neurologic or cardiovascular disease . Cranial and orbital bruits are vibrations resulting from turbulence in intracranial or extracranial vessels . Although usually systolic in timing, these bruits may extend into diastole or even be continuous . These sounds may originate within the cranium or be transmitted from arteries in the neck or, occasionally, from cardiac valvular lesions . The orbits provide relative "windows" for transmission of intracranial sounds, with minimal bony dissipation . Indication for cranial and orbital auscultation usually follows from historical physical examination or laboratory evidence of cranial-cervical disorders such as seizures, headaches, stroke syndromes, intracranial mass lesions, or carotid bruits . Neck auscultation is commonly indicated for initial evaluation of stenotic or embolic cerebrovascular symptoms, or as part of a comprehensive physical examination in asymptomatic patients at risk for atherosclerosis . Cervical bruits and hums may arise from neck arteries or veins, and may be innocuous findings or indicate underlying pathology. Bruits arising in the carotid arteries are produced by intrinsic stenosis or, occasionally, with vascular occlusion from extrinsic compression. Depending on a variety of factors, these bruits may be systolic, primarily systolic with extension into diastole, or continuous. The cervical venous hum is auscultated over the internal jugular veins in many normal children . Commonly a continuous high-pitched sound, it is occasionally more prominent in diastole. It occurs more frequently on the right than on the left, and may be present bilaterally . Supraclavicular bruits during systole are a frequent finding in normal children and in adults with subclavian or vertebral artery stenosis . Supraclavicular auscultation is usually initiated to evaluate vertebral artery occlusive symptoms, arm claudication, or "subclavian steal" in the adult with atherosclerosis .