 Good day everybody. Dr. Sanjay Sanyal, Professor, Department Chair. So this is going to be a demonstration of the subclavian and the axillary artery right from the neck all the way to the axilla. This is a subangian ever. I'm standing on the right side. Camera person is also on the right side. This is the brachycephalic trunk which I've lifted up here at the thoracic inlet and from the brachycephalic trunk we can see this branch coming out. This is the common carotid artery on the right side. This is the subclavian artery. This is a digital subtraction angiogram showing right subclavian artery and the right common carotid artery. The subclavian artery has got three parts. The first part is the portion proximal to the scalinus anterior muscle. So therefore the first part is from here to here. Then there's a second part which is behind the scalinus anterior muscle and that portion we have cut and we have taken it out because that's the only way we can see it. And then we have the third part which comes from the scalinus anterior muscle to the outer border of the first trip which is here. After that it becomes known as axillary artery. So these are the three parts of the subclavian artery. So let's take a look at the branches coming out from the first part of the subclavian artery. We see this artery which I have lifted up here. This is the vertebral artery. In the neck it travels in a triangular space which is bounded laterally by the scalinus anterior muscle and medially by a muscle here called the longest coli muscle. So it goes through that triangular space and then it disappears in the deep part of the neck. After that it travels through the transverse foramen of C6-5-4-3-2-1 and then it pierces through the posterior gland occipital membrane and becomes intracranial where it supplies a posterior cerebral circulation. So this is the vertebral artery. This is a three dimensional demo flight spoiled gradient recall MR angiogram showing the vertebral artery. The next branch is this one here. We had to cut it because the rest of the artery is inside the thorax and we can see the cut portion of the artery here. This is the internal thoracic or the internal mammary artery. This runs on the inner surface of the chest adjacent to the sternum. The third branch from the first part is this one which I have lifted up here. This is the thyro cervical trunk. The thyro cervical trunk itself has got four branches and we can see three of those branches. The first is this one here. This is the inferior thyroid artery and I will draw your attention to the course of the inferior thyroid artery and the relationship. We can see the inferior thyroid artery first goes up and then it goes down and it enters into the lower pole of the thyroid gland. This is the inferior thyroid artery and here it is in close proximity to this nerve here. This is the right recurrent laryngeal nerve. It is formed as a branch from the vagus. This is the vagus. We can see it is crossing in front of the subclavian artery on the right side and it is giving this branch here and this branch is then hooking under the subclavian artery and we can see that branch here and this is the right recurrent laryngeal nerve. This is a very important relationship. When we are doing a thyroidectomy and we have to ligate the inferior thyroid artery we are liable to injure the recurrent laryngeal nerve producing hoarseness. So therefore the rule of thumb is well ligating the inferior thyroid artery we should ligate it very far from the gland like what I've shown here with my instrument so as to spare the recurrent laryngeal nerve. This is the inferior thyroid artery. This is one of the terminal branches of the thyroid cervical trunk. The other terminal branch is visible here. This is the other terminal branch. This is the ascending cervical artery which runs up in the neck. The third branch of the thyroid cervical trunk is this artery. This is the suprascapular artery and we can see it is running transversely laterally and it is accompanied by the suprascapular nerve and it is accompanied by the suprascapular vein. The fourth branch is supposed to be transversal cervical but here we cannot see the transversal cervical. Now this transversal cervical the fourth branch of the thyroid cervical trunk is a little controversial. Some books call it cervical dorsal artery and this is supposed to divide into a superficial branch and a deep branch and the deep branch is also referred to as dorsal scapular and I shall show you the dorsal scapular just now from a different branch. So that is about the branches from the first part of the subclavian artery. Now let's come to the second part of the subclavian artery which I told you is behind the skeletonus anterior muscle and as I said we have cut it and we have taken it out. So this portion was behind the skeletonus anterior muscle. This is the branch from the second part and this is the costal cervical trunk. The other part of the costal cervical trunk is here. This costal cervical trunk according to the textbooks ideally is supposed to give two sets of branches. One is a deep cervical which supplies the deep muscles of the neck and the other is the supreme or the superior intercostal which supplies the first posterior intercostal space. Here we will see something a little different. This is the costal cervical trunk and when I'm pulling here you can see this is moving. So this is the other end of the costal cervical trunk and if you go to look here we see that this costal cervical trunk is giving the following branches. This is the first one. This is the supreme or the superior intercostal which supplies the posterior intercostal space the first or the first or second. This is deep cervical which supplies the deep muscles of the neck and this is giving the dorsal scapular artery which I said comes from the transverse cervical but here it is coming from the costal cervical trunk and this is going on the dorsal aspect of the chest and it participates in the scapular and astromosis. Then we have the third part of the subclavian artery which is the portion lateral to the skeletal anterior from the skeletal anterior to the outer border of the first rib. Ideally the third part of the subclavian artery does not have any branches but sometimes it can give rise to the dorsal scapular artery or scapular artery. The important thing about this third part is that it runs through this triangular space bounded by the skeletal anterior medially and the skeletal medius laterally and bounded by the first rib below. This triangular space is referred to as the skeletal triangle and the third part is running through the triangular space along with the upper trunk, middle trunk and the lower trunk of the brachial plexus and either or any of these can be compressed in an abnormal insertion of the skeletal anterior muscles or by a cervical rib or by many other factors and that is referred to as the skeleton syndrome or the osteoclavicular syndrome or the thoracic inlet syndrome. So this is about the subclavian artery. Now we shall continue and we will see the axillary artery. The axillary artery starts from the outer border of the first rib and it ends at the lower border of the t-rease major muscle. So therefore this is the extent of the axillary artery where my two fingers are located and this is the axillary artery that I have picked up here. It runs in the axilla and then it continues into the arm of the brachial artery. Let's take a look at the part of the axillary artery. The axillary artery has also got three parts. The first part is from the outer border of the first rib to the upper border of the pectoralis minor which was here. So this much is the first part. Second part is behind the pectoralis minor so this much is the second part. The third part is from the inferior border of the pectoralis minor to the lower border of the t-rease major. This much is the third part. And the branches are one, two, three. From the first part we have one branch and we can see the branch here. This is the superior thoracic artery. This supplies the upper anterior chest wall. From the second part we have two branches. This is the first one of the two branches and we can see this is supplying the lateral side of the chest wall. This is the lateral thoracic artery. The lateral thoracic artery runs with the long thoracic number of bell which I have picked up here and it runs on the side of the chest wall and supplies the sedatus anterior muscle and this lateral thoracic artery also gives multiple branches to the female breast which are known as lateral mammary branches. That's one branch from the second part. Another branch from the second part is this composite which I picked up here. This is the thoracoacromial artery. The thoracoacromial artery has got four sub branches. A pectoral branch, deltoid branch, acromion and a clavicular branch. And this thoracoacromial artery pierces through the postocorochoid membrane along with the lateral pectoral nerve and supplies all these branches. So these are the two branches from the second part. Now let's come to the third part. The third part has got three branches. We can see this branch here. This is the posterior circumflex and we can see the posterior circumflex is accompanying the axillary nerve through the quadrangular space. This is one branch. There should be an anterior circumflex but we cannot see it very clearly here which is the second branch from the third part. And the final branch from the third part is this big artery. This is the sub scapular artery. The sub scapular artery as it continues down it divides into two major branches. And one of that we can see here this is the thoracodorsal artery which accompanies this nerve. This is the thoracodorsal nerve and we can see it is supplying the latissimus dorsi. And the other branch is the circumflex scapular which goes through the triangular space and participates in the scapular anastomosis. So these are the three branches from the third part and after that axillary artery becomes continuous as the brachial artery. I need to tell you something about the scapular anastomosis. The scapular anastomosis is an anastomosis around the scapula. It's basically an anastomosis between the branches of the first part of the subclavian artery which I mentioned just now. More specifically branches of the thyrosurvicar trunk namely the supra scapular artery and from branches of the third part of the axillary artery. More specifically the sub scapular artery and its branches namely the circumflex scapular artery. This scapular anastomosis plays a very important role when there is a subclavian or proximal axillary occlusion. This is the digital subtraction agigram showing collateral circulation in proximal axillary occlusion. Because of this scapular anastomosis if it is necessary to like it the axillary artery we should do it proximal to the sub scapular branch so that the sub scapular artery through the scapular anastomosis can feed the circulation and continue to feed the arm. Another point I need to remind you is that as I mentioned the subclavian artery passes through the skeleton triangle but what about the subclavian vein? The subclavian vein is this one here. The subclavian vein is formed as a continuation of the axillary vein on the medial side of the axillary artery. The subclavian vein does not pass through the skeleton triangle instead it passes anterior to the skeletonous anterior muscle. So therefore the problems of skeleton triangle do not apply to the subclavian vein. However the point to be noted is behind the subclavian vein is this nerve. This is the phrenic nerve. Phrenic nerve runs in front of the skeletonous anterior muscle and it goes behind the subclavian vein as we can see here. So this is running behind the subclavian vein. Rarely we can have an axillary phrenic nerve coming from the nerve to subclavius which can be in front of the subclavian vein and it can unite with the main phrenic nerve in which case this axillary phrenic nerve can entrap or compress the subclavian vein. These are all the points which I want to tell you about the subclavian and the axillary artery with their branches and their distribution. Thank you very much for watching. Dr. Sanjay Sanyal signing out. David Oh is the camera person. If you have any questions or comments please put them in the comment section below. Have a nice day.