 Good day everybody. Dr. Sanjay Sanyal, Professor, Department Chair. This is going to be a quick demonstration of the pectoral region. This is supine cadaver. This is the right side. We have completely dissected out the right pectoral region and the muscle that you see in front of us. This is the pectoralis major. Just to bring up to speak, my finger is tracing the clavicle here. So therefore these fibres that you see coming down, these are the clavicular fibres of the pectoralis major. And from here onwards, these are the sternocostal fibres. They take origin from the lateral margin of the sternum and the costal cartilages. And the lower bones fibres, they also take partial origin from the aponeurosis of the external oblique muscle and I have lifted it up here. These fibres then converge laterally and as they converge, they also undergo a little bit of twisting motion. Such that the superior fibres are more superficial and the lower fibres, they go deep. And this is what we can see here. And they get inserted onto the lateral lip of the HRT burglar sulcus. Sometimes there may be a perso between these twisting fibres to prevent friction. The pectoralis major is supplied by the lateral and the medial pectoral nerve which I should show you when I reflect the pectoralis major. The clavicular head is responsible for flexion of the arm at the shoulder joint and the sternocostal head brings back the arm from the flex position. The pectoralis major is responsible for medial rotation and adduction of the arm. The pectoralis major in the female acts as the bed of the breast because the breast is situated here and there is a retro mammary space which is the plane of dissection which is filled with an aerial tissue just anterior to the pectoralis major which serves the plane for dissection during mastectomy. When we are doing breast implants we can do it either under the pectoralis major or on the surface of the pectoralis major. If you take a look at this border of the pectoralis major, the lateral border, you can see that it's free. This is the one which constitutes anterior fold of the axilla and this becomes prominent when we ask the patient to hold his waist tightly and that is one of the methods of examination. And a vertical line drawn along the anterior fold of the axilla also constitutes what is known as the anterior axillary line. That is used as a landmark during various clinical procedures. And the pectoralis major also constitutes the anterior part of the anterior wall of the axilla. That brings me to the next point here, this triangular space. This triangular space that we see here is the delta pectoral and the clavipectral triangle and further down the same triangular space is continuing down as the delta pectoral grew. So as the term implies, it is bounded laterally by the deltoid muscle, it is bounded medially by the pectoralis major and superiorly it is bounded by the clavicle. And this floor is composed of the costochorocoid membrane which we have removed. And it is pierced by this vein here, this is cephalic vein and this also tributary of the cephalic vein. It is also pierced by the thoracochromial artery and the lateral pectoral nerve which I shall show you when I reflect the pectoralis major. And lymphatics which go from the inter pectoral nodes directly to the central group of lymph nodes. There is a band of fascia which comes down from under the clavicle which is not visible here and there is a muscle under that called the subclavius muscle. That is the fascia, the subclavius which actually is continuous with the costochorocoid membrane. And that further continues down and I shall show you the continuation of that fascia once I reflect the pectoralis major. Now I am reflecting the pectoralis major, I have cut it at its origin from the clavicle and from the sternocostal head all along up to the lower part of the ribs. And I am reflecting it, we can see the neurovascular structures on the under surface. These are the neurovascular structures, so let us take a look at the nerves. This is part of the medial pectoral nerve. Medial pectoral nerve pierces the pectoralis minor and it supplies the pectoralis major. So we can see the medial pectoral nerve piercing the pectoralis minor and it supplies the pectoralis major. Now that we have reflected the pectoralis major we can see the clavipectro triangle or the delta pectoral triangle more clearly. But before that let me just quickly describe the pectoralis minor. We have cut that also but let us assume that it was continuous. So this is the pectoralis minor, this one. So we can see that as per the textbook description it takes origin from the third, fourth and the fifth rib. So these are the fibres of the pectoralis minor and the fibres then go up and they get inserted onto the coracoid process where my finger is located. The pectoralis minor helps to protect the scapula shoulder. It brings the scapula downwards and forwards and fixes it during movements of the shoulder girdle or the pectoral girdle. The pectoralis minor forms a very important bridge over the axilla and it is the pectoralis minor which divides the axillary vein and the axillary artery into a first part which is proximal, second part which is behind and the third part which is distant. The pectoralis minor also marks the location of the central group of lymph nodes which are located behind the pectoralis minor in relation to the second part of the axillary vein. Now we have cut the pectoralis minor here and I am reflecting the pectoralis minor here up and I am reflecting the other portion here. So this way we have completely exposed the axilla but the axillary description is going to be for part of our next section. Let me show you the structures which we can see coming out from the clavipectro triangle. We can see this is the lateral pectoral nerve. So the lateral pectoral nerve pierces the costocorochoid membrane. We have already removed it but the pectoralis minor was also covered by a continuation of the same fascia, the costocorochoid membrane which enclosed it anteriorly and posteriorly. And that is the fascia of the pectoralis minor. And coming out from the lateral border of the pectoralis minor was the suspensory ligament of the axilla which also we have removed which was attached to the base of the axilla that is the axillary fascia. This suspensory ligament of the axilla is the one which is responsible for producing the hollow of the axilla when we lift up our arm. That has been removed in order to expose the axilla. The pectoralis minor is supplied by the medial pectoral nerve which I have already shown you here. The pectoralis major is supplied by both medial pectoral nerve and the lateral pectoral nerve. The lateral pectoral nerve pierces through the costocorochoid membrane. The next muscle that we see here deep are the serratus anterior fibres. The serratus anterior takes origin from the second to the ninth ribs and you can see the digitations of the serratus anterior. And the fibres then they go posteriorly along the chest wall and they get inserted under the scapula. And before I conclude I would like to draw your attention to some structures which I have already clipped here. We can see this small neurovascular bundle here, we can see another one here, we can see another one here. These are the perforating branches of the internal thoracic artery which runs behind on the posterior aspect of the anterior chest wall just next to the sternum. And they give perforating branches which pierce through the chest wall and they supply the chest and especially in fibres they constitute the medial mammary arteries which supply the breast. And these are also accompanied by the anterior intercostal cutaneous branches of the intercostal nerves. So these are the structures which I wanted to show you. Thank you very much for watching. Dr. Sanjeev Sanyal signing out. If you have any questions or comments please put them in the comment section below. Have a nice day. Mr. Kendall Kumberbatch is the camera person.