A rather large number of different anatomic variants of intracranial dural venous sinuses are known, and they are found so often that interpreting them only as anomalies is unlikely, except for variations such as sinus aplasia or doubling, which can be attributed to anomalies of the venous system. Diameter reduction (hypoplasia) of the transverse and sigmoid sinuses is observed relatively often. In cases of dural sinuses anomalies, sinuses on the contralateral side are necessarily evaluated as the main source of compensation. When diagnosing dural sinus thrombosis, it is necessary to have a clear idea of the structure of the cerebral venous system, so as not to mistakenly accept hypoplasia or sinus aplasia for thrombosis. Our own experience is based on the results of a neuroimaging study of cerebral veins and venous sinuses in 103 patients (average age 35±10 years) with a tension-type headache. Hypoplasia of the transverse and sigmoid sinuses was detected in 21 (22.4%) cases. In 10 cases (6 men, 4 women), a connection was established between hypoplasia of the dural sinuses and thrombosis. Four patients, presented with hypoplasia of the right transverse and sigmoid sinuses and 6 patients with hypoplasia of the left transverse and sigmoid sinuses. Thrombosis developed on the side of sinus hypoplasia (9 patients) or on the contralateral side (1 patient). Early diagnosis of cerebral venous thrombosis is crucial because the use of anticoagulants reduces the risk of a poor prognosis, severe disability without an additional increase in the risk of brain hematomas progression.