Okaiimas Fol. anat. jap., 48: 413-426, 1972 A Case of the Bilateral Superior Venae Cavae With Some Other Anomalous Veins By Yasumichi Fujimoto, Hitoshi Okuda and Mihoko Yamamoto Department of Anatomy, Osaka Dental University, Osaka (Director : Prof. Y. Ohta) With 8 Figures in 2 Plates and 2 Tables -Received for Publication, July 24, 1971- A case of the so-called bilateral superior venae cavae after the persistence of the left superior vena cava has appeared relatively frequent. The present authors would like to make a report on such a persistence of the left superior vena cava, which was found in a routine dissection cadaver of their school. This case is accompanied by other anomalies on the venous system ; a complete pair of the azygos veins, the double subclavian veins of the right side and the ring-formation in the left external iliac vein. Findings Cadaver : Mediiim nourished male (Japanese), about 157 cm in stature. No other anomaly in the heart as well as in the great arteries is recognized. The extracted heart is about 350 gm in weight and about 380 ml in volume. A. Bilateral superior venae cavae 1) Right superior vena cava (figs. 1, 2, 4) It measures about 23 mm in width at origin, about 25 mm at the pericardiac end, and about 31 mm at the opening to the right atrium ; about 55 mm in length up to the pericardium and about 80 mm to the opening. The vein is formed in the usual way by the union of the right This report was announced at the forty-sixth meeting of Kinki-district of the Japanese Association of Anatomists, February, 1971,Kyoto. 413 414 Y. Fujimoto,H. Okudaand M. Yamamoto internal jugular and the two subclavian veins, and passes downward, attached to the right phrenic nerve anterolaterally and the vagus nerve posteromedially, up to the right atrium. It en route receives the following veins :—Into the anterior wall the right internal thoracic (ca. 9 mm in width), the inferior thyroid (ca. 2.3 mm) and the right pericardiacophrenic (ca. 3.8 mm) ; into the medial wall the thymic (two in number, ca. 6 mm and 1.5 mm) ; into the posterior wall the right vertebral (ca. 11 mm) and the right azygos veins (ca. 15.7 mm). 2) Left superior vena cava (figs. 1, 2, 3, 4) It measures about 23 mm in width at the origin, about 25 mm at the pericardiac end, about 32 mm at the opening to the coronary sinus ; about 58 mm in length up to the pericardium and about 118 mm to the sinus. This vessel, formed by the union of the left internal jugular and the subclavian veins, descends, crossing in front of the aortic arch, then pierces the pericardium in front of the left pulmo- nary artery, and reaches the back of the heart passing between the left auricle and the left upper pulmonary vein. Distal to the piercing, the vessel is attached to the left phrenic nerve anterolaterally and the vagus nerve posteromedially. Then it obliquely passes over the surface of the left atrium and bends along the coronary sulcus. It transfers to the coronary sinus receiving the great cardiac vein, and finally continues rightward for the opening into the right atrium. This vessel is the same in width as the right corresponding vessel before piercing the pericardium, then gradually grows larger. It en route gathers the left internal thoracic (ca. 6 mm) and the left pericardiacophrenic (ca. 1.5 mm) into its anterior wall, the Rr. mediastinales (ca. 1.5 mm) into its medial wall, and the left vertebral (ca. 9 mm) and the left azygos veins (ca. 9 mm) into its posterior wall. No anastomotic branch is observed between the right and left superior venae cavae. 3) Coronary sinus (figs. 3, 4) The sinus is the continuation of the left superior vena cava. It becomes dilated in the shape of a wide spindle (ca. 32 mm in width, ca. 40 mm in length). The great cardiac vein (ca. 6 mm in width) ascends in the anterior interventricular sulcus and turns rightward in the coronary sulcus being covered with the left auricle, parallel with the left superior vena cava, then finally enters the sinus at about 36 mm from its right lower end, where the vessel has a bicuspid valve. The middle cardiac vein (ca. 8 mm) has a monocuspid valve. The posterior veins of the left ventricle are fine, four in number. The sinus which receives the above-mentioned branches flows into the right atrium A Case of the Bilateral Superior Venae Cavae 415 in contact with the orifice of the inferior vena cava (fig. 4). 4) Interior of the right atrium (fig. 5) The attitude of the openings of the right superior and inferior venae cavae follows the usual way. The foramen ovale is completely closed. The opening of the coronary sinus is oval (ca. 28 x 18 mm), and is protected by the valvula of the sinus which adheres to the anterior end of the valvula of the inferior vena cava and makes a _ small sac (ca. 7 mm in depth) between both valvulae. B. The azygos veins (figs. 4, 6) This venous system is made up of bilaterally symmetrical azygos veins, though the left fellow (ca. 9 mm in width) is thinner than the right one (ca. 15 mm). The vein of each side from the ascending lumbar vein runs upward on the anterolateral surface of the thoracic column after piercing the diaphragm, then arches forward in the height of Th IV. The vein passes above the pulmonary root to flow into the superior vena cava of the respective side just before it pierces the pericardium. The opening of the left azygos is slightly lower than the right one. The tributaries of the veins are almost same on both sides. The second and third (second to fourth on left side) posterior . intercostal veins are drained by a common stem, the superior intercostal vein, then flow into the upper end of the azygos. The fourth to eleventh (fifth to eleventh on left side) posterior inter- costal and the subcostal veins directly open into the azygos. The first posterior intercostal vein follows the supreme intercostal vein which drains into the vertebral vein, and communicates with the second posterior intercostal vein. No communication is observed be- tween the azygos veins of both sides. C. Right double subclavian veins (figs. 1, 2, 4, 7) The veins (ca. 33 mm in length) in this case consist of two chan- nels, anterior (ca. 30 mm in width) and posterior (ca. 10 mm). They, holding the M. subclavius between them, drain into the right internal jugular vein ; the anterior channel into the lateral wall of the lower end of the internal jugular and the posterior channel into it in con- tact with the anterior channel inferoposteriorly. (a) Veins joining the anterior channel i) External jugular vein : It (ca. 5 mm) begins by the confluence of the posterior auricular and the occipital veins, and enters the superior wall of the middle of the channel. It is provided with two bicuspid valves both at lower end and in the middle. ii) Anterior jugular vein (ca. 3.5 mm), anteromedial to the join- ing of the external jugular. 416 Y. Fujimoto, H. Okuda and M. Yamamoto iii) Thoracoacromial vein (ca. 5 mm), lateral to the external jugular. iv) Vv. pectrales (ca. 1 mm). v) A confluence (ca. 4 mm) of the transverse cervical and the suprascapular veins, near the termination of the anterior channel. Besides the right lymphatic duct joins the confluence. vi) Corresponding vein (ca. 2 mm) of the ascending cervical artery, at the right venous angle. (b) Veins joining the posterior channel Only the dorsal scapular vein (ca. 1 mm) unites with the con- fluence of the transverse cervical and suprascapular veins. The left subclavian vein is single and not noteworthy. D. Left external iliac vein (figs. 6, 8) The vein divides into two channels, lateral and medial, just before joining the left internal iliac, so a ring-formation (ca. 20 mm in length) is observed. The lateral channel (ca. 5 mm in width and 9 mm in length) receives the iliolumbar vein communicating with the ascending lumbar into the superolateral wall. The medial one (ca. 11 mm in width and 13 mm in length) does not receive any vein. Both channels hold the iliolumbar artery from the internal iliac between them. Discussion The present report was the second case of the bilateral superior venae cavae found in the cadavers which have been dissected at this university. The latest case of the bilateral superior venae cavae in Japan was reported by Chiba et al. (1971). Hitherto in Japan 45 cases have been reported ; 43 Japanese, 1 Chinese and 1 Formosan. Of them, adults who died at ages over 16 years numbered only 26. On the other hand in Europe and America 216 cases were reported by 1946 (Sanders 1946). On the frequency of the bilateral superior venae cavae have been described by many authors as follows ; Adachi (1933) 4 in 821 cases (0.5%), Mukai (1934) 1 in 679 cases, Yamada (1934) 2 in 125 cases (fetuses and newborns), Sanders about once per 348 cadavers. The bilateral superior venae cavae have been classified by Mc- Cotter (1915), Donadio (1925), McManus (1941), Nandy et al. (1965), and Yamadori et al. (1966) etc. ; it was considered that the classifi- cation made by Yamadori et al. might be considerably adequate. Compared with other author's classification, the modification of A Case of the Bilateral Superior Venae Cavae 417 _(4 4) u) 4) 4 d c0 4)..., = Fic .4-, ...o va .4;1 TO i e 2:1 vef .4 4.), Td co C ,4•,.