Brachiocephalic Veins – Thoracic Vessels

00:00 Now, we’ll take a look at the brachiocephalic veins and their tributaries. We mentioned earlier that the right and left first posterior intercostal veins or tributaries, but now, let’s take a look at some of the others. The brachiocephalic veins in this illustration are here for the right brachiocephalic vein. Your left brachiocephalic vein is shown here and again, it is longer than the right one. The tributaries to point out will be the internal thoracic vein, the inferior thyroid vein and then the last one to reference will be the left superior intercostal vein. This slide demonstrates the internal thoracic vein. It’ll be a right internal thoracic vein and a left internal thoracic vein. The right internal thoracic vein is shown here and it’ll empty into your right brachiocephalic vein.

00:59 It’ll run and accompany the internal thoracic artery. Your left internal thoracic vein is running on the left margin of the sternum and will empty blood into the left brachiocephalic vein. The internal thoracic veins are going to be formed by the union of the superior epigastric veins and the musculophrenic and these veins will convey blood from the territories supplied by the arterial counterparts. The left superior intercostal vein is going to drain the more superior posterior intercostal spaces on the left. And those spaces are typically intercostal spaces 2 and 3. Once it does so, it will form the left superior intercostal vein that courses over the aorta, arch of the aorta and then, will empty into the left brachiocephalic vein. In addition, the left bronchial vein would empty in to your left superior intercostal vein. And then the left superior intercostal veins are simply going to drain the territory supplied by the posterior intercostal arterial counterparts. And because you have a left bronchial vein being a tributary, you’ll have some blood being drained from the lung. We also have inferior thyroid veins that are tributaries of the brachiocephalic vein. And we see those inferior thyroid veins located here. They are going to dive posterior to the manubrium, right in the vicinity of the jugular notch that we see here. And then you can see those inferior thyroid veins emptying into the left brachiocephalic. These will help drain blood from the esophagus, larynx, trachea, as well as the thyroid gland and parathyroid glands. The thyroid gland is here.

03:18 This would be the left one. The right portion of that gland has been removed.

03:25 Now, we’re looking at the veins of the vertebral column and there are venous plexuses that are associated with the vertebral column. There’s an external venous plexus and we see some of the elements of the posterior venous plexus on the anterior portions of the vertebral bodies. And then we also have some components of the external vertebral plexus that are located along the posterior vertebral arch components here. The internal vertebral plexus is within the vertebral foramen, as we see in through here. And then within the body of the vertebra, you can see some fairly significant veins that will then join and empty into the internal venous plexus and this large vein that comes out of the vertebral body is referred to as the basivertebral vein. And then you have interconnecting veins between the internal venous plexus and the external venous plexus. And these are the intervertebral veins. Blood that makes its way into the external vertebral venous plexus, this plexus does have anastomotic connections or anastomoses with your posterior intercostal veins. In addition, veins of the spinal cord can drain into this system. Now, we’re shifting our attention to a structure that makes a brief appearance in the thoracic cavity and this venous structure is your inferior vena cava. Most of it lies within the abdominal cavity, within the retroperitoneum and once it enters the thoracic cavity by passing through the caval hiatus in the diaphragm, it will do so at vertebral level T8. It’s going to be a very, very short venous structure because the right atrium is there to receive it. So, it’s only about 2.5 cm in length within the thoracic cavity. And we do see the cut edge of the inferior vena cava here and where it’s cut, it’s been cut from the right atrium. That now brings us to our summary slide. So, what are some of the key take-home messages from this lecture? First, branches of the pulmonary trunk and branches (direct and indirect) of the aorta supply thoracic structures. The aorta within the thorax is divided into the following parts: ascending, arch and descending (the thoracic portion).

06:22 The aortic arch normally gives rise to three branches, though variations may be present.

06:31 And pulmonary veins and tributaries of the azygos vein drain most of the thoracic structures.

06:40 Thank you for joining me on this lecture on arteries and veins of the thorax.