Objective. To conduct an intravital study of the variants of ectatic development of the lower extremity intramuscular veins in patients with chronic venous disease according to multispiral computed tomography (MSCT) phlebography. Subjects and methods. In the period 2015—2018, the developed procedure for MSCT phlebography was used to examine 400 males and females with chronic venous diseases: 108 (27%) patients had clinical class C0—C1; 173 (43.3%) had class C2—C3, and 119 (34%) had trophic disorders (C4—C6). The studies were performed on a Philips Ingenuity 128-slice multispiral computer scanner with the Intell-Space-Portal software package for processing three-dimensional images. Results. Among the examinees with class C0—C1 diseases, the cylindrical intramuscular veins were present in 63.6%, and ectasia of these veins was in 36.4%; among those with clinical class C2—C3, those were present in 10.9 and 89% of cases, respectively; among the patients with clinical classes C4—C6, the cylindrical shape was seen in 12.6%, and intramuscular venous ectasia of various extent was observed in 87.4%. Six main ectatic developmental variants included isolated gastrocnemius venous ectasia unassociated with the varicose segment of the saphenous veins; isolated soleal venous ectasia unassociated with the varicose segment of the saphenous veins; combined gastrocnemius and soleal venous ectasia unassociated with the varicose segment of the saphenous veins; gastrocnemius ectasia associated through the perforating veins with the varicose segment of the saphenous veins; soleal venous ectasia associated through the perforating veins with the varicose segment of the saphenous veins; combined gastrocnemius and soleal venous ectasia associated through the perforating veins with the varicose segment of the saphenous veins. Variants with local and extended venous ectasia of the gastrocnemius and soleal collectors (a total of 12 variants) were also identified. An analysis of the findings could lead to the conclusion that local or extended gastrocnemius or soleal venous ectasia unassociated with the varicose segment of the saphenous veins was extremely rare and accounted for no more than 5.6%. Among the available leg intramuscular venous ectasias, the most common variants of its development are isolated soleal venous ectasia associated through the perforating veins with the varicose segment of saphenous veins (29%), and combined ectasia (59.6%). Conclusion. The conducted studies has led to the conclusion that in developing pathological venous hypervolemia in patients with varicosity, the soleal venous collector versus the gastrocnemius one is more prone to ectasia, the type of which is becoming more expressed and extended. When overloaded with an additional blood volume, the leg intramuscular venous collector ceases to work effectively, continuing to deposit a certain amount of blood, being prone to more extended ectasia.