 demonstration of the surgical aspects of the thyroid gland. We can see the muscles covering the thyroid gland. These are the infrared hyoid strap muscles. The first layer of infrared strap muscles is this one which I am reflecting here. We have cut it at the top. This is the sternohyoid muscle going from the manoeuvrabian sternoid to the hyoid bone and this is the opposite side sternohyoid muscle. Just under that we have this smaller muscle here. This is going from the manoeuvrabian sternoid to the thyroid cartilage and gets attached to the oblique line. This is the sternohyroid on this side and the sternohyroid on this side. If you notice we've cut them on the top because most of the nerve supply comes from below. That's why we always in surgery or so we cut them at the top. The next muscle that we can see here is this one here. This is the thyroid. We have reflected it here and this is the other side. So now we have completely exposed the thyroid gland here. So this is the right lobe, this is the left lobe. The extent of the thyroid gland is from C5 to D1. This is the upper pole, this is the lower pole and this connecting portion is known as the isthmus of the thyroid gland and in this particular cadaver we can see a small projection here from the left side of the isthmus which is called the pyramidal lobe. This is actually a remnant of the thyroglobulosal duct. Sometimes it can be associated with abnormalities of the isthmus itself. We notice these important neurovascular structures and let's take a good look at them. This artery that we can see here, this is a branch from the external carotid artery. This is the superior thyroid artery which enters the superior pole of the gland and ramifies inside the gland from the anterior and lateral aspect. And this superior thyroid artery is accompanied by this nerve here. This is the external laryngeal nerve which supplies the cricothyroid muscle. When we are doing a thyroidectomy one of the essential steps is to clamp and ligate the superior thyroid artery and cut it. So in real life as you can see they're very close to each other and so therefore there is a likelihood of injuring it. So the rule of thumb is to ligate and clamp it as close to the upper pole of the gland as possible. We take a little bit of the upper pole so that we can spare the external laryngeal nerve. If we injure the external laryngeal nerve then we can reduce paralysis of the cricothyroid and the person will get weakness of the voice. So that is one arterial supply. Now let's take a look at the next arterial supply of the gland. We see this artery here. We can see it is coming out from the thyrosurviger trunk. It is going up looping and then coming down again to the lower pole. This is the inferior thyroid artery. This is a very unique course of the artery and this inferior thyroid artery it enters the lower pole and it ramifies inside of the medial and posterior aspect of the gland. And accompanying this artery is this nerve here. This is the recurrent laryngeal nerve which came from the vagus nerve. This is the vagus. It hooked under the subclavian artery and it went up. So again when we are doing a thyrotectomy we have to be very careful about ligating the inferior thyroid artery and I shall demonstrate it to you just now. When we are trying to ligate and cut the inferior thyroid artery we can see how easy it is to inadvertently catch the recurrent laryngeal nerve. That will lead to vocal cord paralysis and horses of voice. In order to safeguard this we ligate the inferior thyroid artery as far from the gland as possible here. That way we can safeguard the recurrent laryngeal nerve. The thyroid gland is highly vascular and it has got three veins which we are not very clearly visible here except one vein. There is a superior thyroid vein which accompanies the superior thyroid artery. There is a middle thyroid vein which accompanies the inferior thyroid artery and there's an inferior thyroid vein and we can see the inferior thyroid vein here. The superior and the middle thyroid veins they drain into the internal jugular vein. But the inferior thyroid vein runs in front of the trachea and it opens into the left brachycephalic vein and this can be injured when we are doing a tracheostomy. When we are ligating the arteries and the veins we should always ligate arteries first and then the veins. Otherwise there'll be too much of venous congestion and when we are removing the thyroid gland there'll be horrendous bleeding. Goiter is very common and it is more common in females because of iodine requirements. That brings me to some of the surgical procedures that we perform on the thyroid gland. The simplest procedure is what we have done in this category. We just split the isthmus and that is known as isthmusctomy. This is specifically done in a condition known as lignus thyroiditis. When the thyroid is hard, stony hard and it compresses the trachea. You know to relieve the compression we do an isthmusctomy. If a patient has got a solitary nodule, a goiter's nodule in one lobe then we can do just a lobectomy. If a person has got multiple nodules then we have to do what is known as a hemithioticomy. If a person has got multiple nodules on both the sides then we have to do what is known as sub-total thyroidectomy. And if a person has got cancer then we have to do what is known as near-total thyroidectomy. Near-total means we just leave a little bit of thyroid tissue in relation to the posterior aspect of the gland where approximately where menstruate is located to safeguard at least one parathyroid gland. There are supposed to be four parathyroid glands. One, two, three and four. So we should save one at least one to prevent hypocalcemic tetany and therefore we do what is known as a near-total thyroidectomy. So these are some of the surgical procedures that we perform on the thyroid gland. Thank you very much for watching. If you have any questions or comments please put them in the comment section below to sign your signing off. Daniel is the camera person. Have a nice day.