Whether or not you watched video Episodes 081 to Episode 085, you’ll find this video useful to see how well you remember your anatomy of the pectoral muscles. You can choose to identify the parts with Leslie or just listen and watch along as he points out each of them with their origins, insertions, and actions. Great review tool!
Transcript of Today’s Episode
Hello and welcome to another episode of Interactive Biology TV where we’re making Biology fun. My name is Leslie Samuel. In this video, what I’m going to be doing, what we’re going to be doing, this is the review session for the pectoral muscles.
We’re going to over the four pectoral muscles and we’re going to go over the origin, insertion, and the action of those muscles.
So, if you want to quiz yourself and you want to see how good you are, turn the volume down right now, and we’re going to go through these and you can just talk along with me. If you’re just learning it now, you can just play it over and over and over until you get it and you can do it on your own.
So, let’s start with the first muscle. What is the name of this muscle? This is pectoralis minor. The origin would be the anterior surface of ribs three, four, and five near the costal cartilges. The insertion point would be the medial aspect of the coracoid process of the scapula and its action, it helps to stabilize the scapula by pulling it inferiorly and anteriorly against the thoracic wall. That’s pectoralis minor.
The next muscle is subclavius. The origin would be the first rib at the junction with the costal cartilage. The insertion point would be the subclavian groove on the inferior surface of the clavicle. Its action, it depresses the clavicle inferiorly and anteriorly.
The next muscle, the name is serratus anterior. The origin would be the external surfaces of ribs one through eight or nine, and really it’s the lateral parts. I don’t know if I mentioned that in the actual video, but now you know. The insertion would be the anterior surface of the medial border of the scapula. Its action, number one, it stabilizes the scapula, it protracts the scapula, and it helps with upward rotation of the scapula.
Then, there is pectoralis major. The origin, if we’re dealing with the clavicular head, it is the anterior surface of the medial half of the clavicle. For the sternocostal head, it’s the anterior surface of the sternum, the upper six costal catilages and the aponeurosis of the external oblique muscle.
The insertion would be the crest of the greater tubercle of the humerus, or you can call that the lateral lip of the intertubercular sulcus or the bicipital groove. Its action, the clavicular head flexes the humerus, the sternocostal head extends the humerus, and the entire muscle as a whole adducts the humerus, and helps with medial rotation or internal rotation.
That’s pretty much it! How did you do? I hope you did well on that little review of the four pectoral muscles.
If you want more videos like this or other resources to help make Biology fun, you know exactly what to do. You know exactly where to go. And, if you don’t that is interactive-biology.com.
This is Leslie Samuel. That’s it for this video, and I’ll see you in the next one.