 There by Dr. O here in this video, we're going to cover the muscles of the rotator cuff or the rotator cuff muscles, not rotary cuff. I've heard also the different things, but the rotator cuff and it's called that because it does it functions, it braces or puts a cuff around the head of the humorous when the arm moves. And as you'll see, there are there are the tendons and muscles that go over the top of it, the back of it and the front of it. So it wraps, it supports that head of the humorous. So really, all these muscles have their own function, but as the rotator cuff, they also help hold the head of the humorous into its socket, the glenohumeral joint, which remember the glenoid cavity is not really a socket. So these muscles have to stabilize the shoulder. That's why these muscles get so tight and that's why these muscles get torn and tears in the tendons, et cetera, because these muscles are very busy. Anytime your arms are not resting on your side, your rotator cuff muscles have to be contracted. All right. So for rotator cuff muscles, you might see them called SITS. We have supraspinatus, infraspinatus, teres minor, and subscapular. So the supraspinatus muscle is above the spine of the scapula. It's the one that runs over the top forming that cuff from the top and it abducts the shoulder. The infraspinatus is below the spine of the scapula and the infraspinatus and the teres minor, they're both on the back of the shoulder. So they both externally rotate the shoulder and form the back portion of this rotator cuff. Notice I said infraspinatus and teres minor. The teres major, look at the picture there, it inserts on the front of the arm so it functions along with the latissimus dorsi, not part of the rotator cuff. Teres minor, part of the rotator cuff, teres major functions right alongside the latissimus dorsi. Then the last one's a subscapular. It's the hardest one to see, lots of muscles in the way. That's in the subscapular. That's underneath or in front of the scapula. So real big muscle there on the front side of the scapula and its job is medial or internal rotation. I notice golfers, baseball players, people that swing bats in golf clubs, they often have real tight subscapular muscles but that's where that is there. Alright, so that's your rotator cuff. I hope this helps. Have a wonderful day. Be blessed.