 on the muscles of the upper limb. In this session, we will be learning about the muscles of the pectoral region. So, which are which all muscles are included in the pectoral region. So, here is the list of the muscles. We will be learning about the pectoralis major then pectoralis minor and there is a small muscle which is called a subclavius and lastly the serratus anterior muscle. So, these four muscles will be covering in this particular session. So, any muscle when we study we have to cover under specific headings. So, I have listed down those headings. So, we should be knowing about the proximal attachment of the muscle, the distal attachment of the muscle, the nerve supply of that muscle and lastly the actions of that muscle and also related applied anatomy we should be knowing. So, all these headings I will be covering for the muscles which were listed. So, let's start with the pectoralis major muscle. So, pectoralis major where does it originate? pectoralis major muscle it's actually has two heads of origin. This is the clavicular head and this is the sternocostal head. Okay, the clavicular head it arises from the anterior aspect of the medial half of the clavicle and the sternocostal head it arises from the anterior surface of the sternum the second to the sixth costal cartilages as well as some part from the external oblique aponeurosis. Okay, so the sternocostal head has got a little extensive origin which you should be aware of. It has origin from the sternum, it has origin from the costal cartilages as well as there's a small slip of attachment from the aponeurosis of the external oblique muscle. Okay and distal attachment is on the lateral lip of the inter tuberculous sulcus. This thing we had already covered in the humerus. Humerus has got lateral lip, a medial lip and a floor. The lateral lip gives attachment to the pectoralis major. The medial lip of the bicepital groove it gives attachment to the teres major muscle and the floor gives attachment to the muscle that is latissimus dorsi. Okay, so the muscle fibers of pectoralis major they converge and then they insert along the lateral lip of the inter tubercular sulcus. The mode of insertion is such that the lower fibers are twisted and those are inserted near the upper part and the upper fibers are inserted along the lower part. Okay, because of the twisting of these fibers it leads to specific formation of the anterior axillary fold. Okay, so this was about the proximal and distal attachment of the pectoralis major muscle. The nerve supply of pectoralis major. There are two nerves which applies the pectoralis major. One is the medial pectoral nerve and other is the lateral pectoral nerve. Okay, so these two are the branches from the brachial plexus. Medial pectoral nerve will arise from the medial cord. Lateral pectoral nerve will arise from the lateral cord. So the nerve which arises from the lateral cord what is the root value of that nerve of the lat what is the root value of lateral cord C5, C6 and C7 and root value of medial cord of brachial plexus is C8 and T1. Okay, so the entire components of the brachial plexus they are taking part in the nerve supply of the pectoralis major. Okay, C5, C6, C7, C8 and T1. All components are included in nerve supply of the pectoralis major muscle. And talking about the actions of the pectoralis major muscle. So since there are two heads of origin, actions of pectoralis major are also divided into like two parts action of the clavicular head and action of the cernocostal head. Action of the clavicular head of the pectoralis major is flexion of the shoulder joint and the cernocostal head is responsible for adduction and medial rotation. Okay, adduction and medial rotation of the shoulder joint is done by the cernocostal head whereas flexion is done by the clavicular head. Okay, so these are the actions of the pectoralis major. So now let's move on to the, okay, before moving on to the next muscle I have got some dissected photos of the pectoralis major. So here we can see the dissected specimen. This is pectoralis major muscle, this one. This is the clavicular head and this is the cernocostal head. Similarly here also this is the pectoralis major. This is clavicular head here, cernocostal head which is senior. Okay, the muscles are converging towards the lateral aspect and they will get inserted towards the lateral lip of the bicepital groove. Now let's cover the pectoralis minor muscle. Pectoralis minor muscle, proximal attachment or originate is from the third, fourth and fifth ribs. So from the lateral aspect of the third, fourth and the fifth ribs the muscle is originating and it is getting inserted here towards the medial aspect of the corocod process. Okay, so the distal attachment is towards the medial aspect of the corocod process. Nostoplar pectoralis minor is also similar to that of the pectoralis major that is the lateral pectoral nerve and medial pectoral nerve. Okay, lateral pectoral nerve, root value of, root value was C5, C6, C7 and medial pectoral nerve, root value was C8 and T1. Okay, then actions of pectoralis minor muscle. Since this muscle is attached on to the anterior aspect of the scapula, when it contracts it will pull the scapula forward as if in protraction of the scapula. It assists the serratus anterior muscle for protraction of the scapula and it also helps as an accessory muscle for respiration. During forced inspiration this muscle acts as an accessory muscle. Okay, so this was about the pectoralis minor muscle. Let's move on to the dissected images of the pectoralis minor muscle. So here we can see the dissected photos. This muscle is the pectoralis minor. Okay, in this image this is the pectoralis minor. Arising from the third, fourth and the fifth rib then distal attachment is towards the medial aspect of the corocod process. At times it may arise from the second rib also and it may arise from the sixth rib also. There may be variations it may be seen for attachments of pectoralis minor but most of the times you will find that it is attached on to the third, fourth and the fifth rib. Here we can see one more muscle here, this is subclavius muscle. Subclavius muscle arises from the first rib near the costochondral junction and the distal attachment is towards the inferior surface of the clavicle. So along the inferior surface of the clavicle there is a subclavian groove. So this muscle gets attached on to the subclavian groove and now supply of subclavius muscle is nerve to subclavius. Nerve to subclavius it arises from the upper trunk of the brachial plexus. The two nerves which are arising from the upper trunk of the brachial plexus, one is the nerve to subclavius, another nerve is supra scapular nerve. That region is also referred to as herbs point because six nerves are meeting towards that point. So nerve to subclavius arises from the upper trunk of the brachial plexus. Root value is C5 and C6. Actions of subclavius muscle it stabilizes the clavicle during movements of the shoulder joint. So action of subclavius is stabilization of the clavicle. Coming to the serratus anterior muscle. Serratus anterior muscle it has got origin from the upper eight ribs. So here we can see on the lateral aspect of the shaft of the upper eight ribs this muscle is arising or we can say the proximal attachment is from the upper eight ribs and distal attachment or the insertion is towards the medial border of the scapula. Medial border costal aspect. Costal aspect of the medial border of the scapula that is attachment of serratus anterior muscle. There are different digitations like the first digitation gets attached near the superior angle. The next digitation gets attached towards the medial border and last five digitations gets attached along the inferior angle of the scapula. So most of the digitations of serratus anterior gets attached down to the inferior angle of the scapula. Then nerve subclavius serratus anterior it is the nerve arises directly from the roots of the brachial plexus. Root value is C5, C6, C7. Name of the nerve is nerve to serratus anterior. Also it has got two other names. It is also called as long thoracic nerve. It is also called as nerve of bell. So three names for this particular nerve. I will repeat again nerve to serratus anterior, long thoracic nerve, nerve of bell. Having root value C5, C6 and C7 arising directly from the roots of the brachial plexus. Actions of serratus anterior. So serratus anterior is a strong protractor of the scapula. So during pushing and punching movements the protraction of the scapula is done by serratus anterior muscle. In this image also we can see this muscle is serratus anterior, arising from the lateral aspect of the chest wall, binding around the chest wall and getting attached on to the medial border costal aspect of the scapula. Medial border dorsal aspect of the scapula there are other muscles, the levator scapulae, rhomboids minor, rhomboids major. So when we say medial border we have to specify medial border which aspect. Serratus anterior is on the costal aspect. Okay now let's see the dissected picture of the serratus anterior muscle. So here this muscle which you can see this is the serratus anterior muscle. Whenever this muscle gets paralyzed it leads to a clinical condition it is called as winging of the scapula. What is winging of the scapula? It is paralysis of the serratus anterior in which the medial border of the scapula becomes prominent. Why the medial border becomes prominent? Because of the pull of the rhomboids. Rhomboids which are attached on to the medial border dorsal aspect those muscles pull the scapula behind so that leads to the prominent medial border of the scapula. Okay clinical condition is called as winging of the scapula. It is a paralysis of the nerve supplying serratus anterior. Also it is called as long thoracic nerve or nerve of bell. Okay injury most often occurs whenever there is surgery in the breast region. Okay so I've covered all the four muscles. Let's quickly summarize what we have covered in this session. So we started off with pectoralis major muscle proximal attachment. It has got two heads of origin the clavicular head and sternocostal head. Clavicular head arising from the anterior aspect of the medial of the clavicle. Then sternocostal head is arising from the sternum, from the coastal cartilages as well as from the eponeurosis of the external oblique muscle. And distillatization of pectoralis major is along the lateral lip of the bicepital groove. Now circular pectoralis major is by the lateral and the medial pectoral nerves. Okay in action of pectoralis major the clavicular head is responsible for flexion and the sternocostal head is responsible for adduction and medial rotation of the shoulder joint. Okay then pectoralis minor proximal attachment or origin is from the third, fourth and the fifth ribs. Distal attachment of the insertion is on the medial aspect of the corocord process. Now supplies again by the lateral and the medial pectoral nerves. And action of pectoralis minor is it assists to the serratus anterior muscle during protraction of the scapula. Another action is it acts as an accessory muscle of respiration. Then subclavial is a small muscle arising from the first rib near the costochondral junction. Distal attachment is towards the inferior aspect of the clavicle, the subclavian groove. Then nerve supplies nerve to subclavius arising from the upper trunk of the brachial plexus and action is action if it stabilizes the clavicle during movements of the shoulder joints. Then serratus anterior muscle proximal attachment is from the upper eight ribs lateral aspect distal attachment or insertion is towards the medial border of the scapula coastal aspect. Okay then nerve supplies by the nerve to serratus anterior also called as long thoracic nerve also called as nerve of bell. Okay action of serratus anterior is protraction of the scapula. Okay so this was all about this session. If you all have any doubts pertaining to the session you all can ask in the comment section below. Okay thank you.