Hi, it's good to see you again. This is the start of section three the first lecture, I will start with an overview of what you can expect in this section. The first lecture is going to inform you about which muscles make the shoulder move. Like I said in earlier sections anatomy basics is not covering each and every small muscle in the body. The reason for that is that it will not keep your attention that long. You may be doing this course because you're into sports like fitness, bodybuilding, or any other kind of training.

You may be a caretaker in sports or otherwise interested. You might even be a physiotherapy student or a medical student. But again, getting into every little detail might be too much information to keep you interested. In this first lecture, the shoulder is our topic. In the following lectures, we will explore the muscles around the elbow and the wrist. After that, we will take a look at the muscles of the hand.

You might be hesitant because of all the difficult names you expect to hear. But remember, there is the dictionary to help you out. And I promise to take it slow and step by step. Now that you know the various movements, as explained in Section two, let's take a look at the forward flexion of the shoulder. There are four muscles that contribute here. biceps, coracle, brachialis, pectoralis major and deltoid.

Probably you know the biceps a little already, biceps means to hit the one head starts here at the super glenoid to berkelium and then rolls over the humerus head along the sulcus further down to the proximal part of the radius, where it attaches at the rough surface called the radial tuberosity. The second head of biceps starts at the coracoid process. Enjoy The muscle belly of the long head halfway to become one muscle. The next important muscle in forward flexion is Cora corporate Keolis. Its origin is the coracoid process as well as the insertion is at the humerus bone, the Latin word for armors break I, hence the name of this muscle. The major chest muscle pectoralis major has three parts actually, each with a different function.

Its origin is partly on the clavicle for the upper fibers. Then here on the ribs and sternum for the middle fibers. And down here, the abdominal origin for the lower fibers. The insertion at the humerus which is upside down, the upper fibers attached distally and the abdominal fibers approximately pectoralis major has an important function and we'll return in other movements but for forward flexion The upper fibers are active. Then we have the last muscle that contributes to forward flexion deltoid. This is like pectoralis major another muscle with multiple aspects.

Let's start with where it begins and ends. The origin is V shaped when you look at it from above. In fact, the anterior fibers start from the distal part of the clavicle. The middle fibers from the acromion and the posterior fibers start from the scapular spine, all without tendons, they all form one muscle belly that has its insertion at the deltoids tuberosity. A rough surface on the humerus bend. The anterior fibers help the arm and forward flexion now the opposite movement extension of the shoulder is possible By the activities of five muscles, two of them we already met pectoralis major and deltoid.

An extension of the shoulder the active part of these two muscles are the lower fibers of pectoralis major and the posterior fibers of deltoid. Adding to these two we see another three muscles helping out, petition Mr. Dorsey. This large wing like muscle looks like a tower wrapped around the trunk. Its origins widespread, the lower angle of the scapula, the upper neurosis of the thoracic and lower back and even part of the iliac crest. From there without a tendon the fibers converging to the insertion on the humerus at the front side. The whole muscle is active in extension, swimmers extend a lot and you can see that in the volume of the latissimus dorsi.

The fourth muscle for extending His triceps break high, the three headed muscle of the arm. The lung by articular head starts at the info glenoid to berkelium. And it's to mono articular parts have their origin from the humerus bone and outer lateral head and an inner medial head. Together. These three have one insertion on the electron on the honor an extension of the shoulder joint only the by articular long part of triceps can deliver power. The fifth and last muscle for extension of the shoulder is Tara's major.

This muscles origin is just above the inferior angle of the scapula. And from there the fibers blend in with latissimus dorsi and they share the same insertion. Note that using the extension function could be kayaking, climbing up a rope, swimming and walking on crutches Let's move on to the next two movements, abduction and adduction. abduction is caused by two muscles, the deltoid with both anterior and posterior fibers and supraspinatus. supraspinatus starts from the super scapular fossa and inserts at the major tuberculin of the humerus bone. abduction, on the contrary is done by no less than seven muscles.

The good news here is you know five out of seven already, namely latissimus dorsi teres major pectoralis fibers help here. coracle brachialis and triceps brachii the long head but to other muscles attribute Adapting. First we see infraspinatus it arises from the infra scapula fossa. Its fibers converge and insert at the major tuberculin right beneath supraspinatus. The second new muscle is terrorists minor. It starts from the lateral reach of the scapula right above terrorists major.

Terrorists minor inserts at the major tuberculin at the posterior side. Now we have looked at the function of a lot of muscles, and I hope you're still with me. We are now ready for the last two directions in which the shoulder can move inner and outer rotation. External or outer rotation is mainly done by infraspinatus. We met infraspinatus as an adductor and there are two other muscles for external rotation that we know already. Namely terrorists minor and deltoid.

It's posterior fibers. So that was a quick summary for auto rotation. There are no new muscles involved. Internal or inner rotation is our last movement to discuss. In total five muscles are responsible for internal rotation. Four of them are old acquaintances already, namely, the dismiss Dorsey and its shadow terrorists major terrorists major inserts with latissimus at the front side of the humerus causing internal rotation.

Deltoid is helping out with its anterior fibres and pectoralis major is active. The new muscle we have to meet is subscapularis. The origin of this muscle is the anterior side of the scapula. The side that is against the ribs actually, from there, it converges towards the head of the humerus and insert at the minor to berkelium which is at the anterior side of the humerus bone. Well, that was a lot to take in, I suppose. This was a heavy lecture, but you made it till the end.

Hopefully you want to continue with lecture two to learn about the muscles of the elbow and