Pulsatile tinnitus is a symptom rather than a diagnosis: a sound synchronous with the heartbeat that may arise from venous, arteriovenous, arterial, tumoural or otological causes. Assessment begins by confirming pulse synchrony and excluding dangerous lesions, notably dural arteriovenous fistula, arterial dissection and paraganglioma, before a venous explanation is accepted. The most frequent treatable cause is transverse sinus stenosis, often accompanied by a sigmoid sinus wall anomaly that transmits the sound; the same stenosis is common in idiopathic intracranial hypertension, with which pulsatile tinnitus overlaps. Venous sinus stenting resolves the tinnitus in most carefully selected patients, but selection rests on concordance between symptom, anatomy and venous pressure measurements, and the supporting evidence remains observational.