This video will talk about the nerves that innervate the pectoral muscles. These nerves are the lateral and medial pectoral nerves, and the long thoracic nerve. Watch to learn more.
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 and in this video, I’m going talk about the innervations of the pectoral muscles.
If you want to do some push-ups, you got to get some signals going to those pectoral muscles and we need nerves to do that, motor nerves to do that. That’s exactly what we’re going to talk about in this video. Let’s get right into it.
The first pectoral muscle that we’re going to talk about is pectoralis major. You can see it over here. At the left, you can see it’s a relatively large muscle. That gets innervated by two nerves.
The first one that it’s going to get innervated by is called the lateral pectoral nerve which makes sense. You have the lateral pectoral nerve coming off the lateral cord of the brachial plexus. Then, it’s also going to get innervated by the medial pectoral nerve which you can see here coming off that medial cord.
So, pectoralis major is going to get innervated by the lateral pectoral nerve and the medial pectoral nerve which makes sense based on the name. We’re going to have a lateral and the medial but, they’re both pectoral nerves coming off of the respective cords.
Then, we have pectoralis minor which you can see here in the picture at the left. That one is actually going to get innervated by only one of the pertoral nerves. The one that wins for that guy is the medial pectoral nerve.
This is how I remember it. There’s a lateral pectoral nerve and there’s the medial pectoral nerve. Lateral is going to do less, and medial is going to do more. So, we have the ‘L’ for ‘lateral,’ ‘L’ for ‘less,’ the ‘M’ for ‘medial’ and the ‘M’ for ‘more.’ So, the medial pectoral nerve is the one that’s doing more work. It’s giving innervation, it’s providing innervation to both pectoralis minor and pectoralis major. Lateral is less, medial is more, and that’s a quick and easy way to remember that.
Then, we have subclavius. This is probably one of the easiest ones to remember because we have a nerve that’s called the nerve to subclavius. You can see that right here. That nerve is coming off of the superior trunk of the brachial plexus.
Just as a reminder, if any of these brachial plexus nerves sounds strange or you’re not exactly sure how these all comes together, make sure to go back and check out my video on the brachial plexus where I show you exactly how to draw this entire thing and you learn all of the nerves very quickly. The nerve to subclavius is the one that’s innervating the subclavius muscle. It comes directly off of the superior trunk of the brachial plexus.
Lastly, we have serratus anterior, which is this muscle that you see here on the guy over here to the left. That one, the way I remember the nerve that innervates serratus anterior, this is the one that tastes good. This is the one where you salt — SALT:
Serratus Anterior gets innervated by the Long Thoracic nerve.
You can come over here and see that the long thoracic nerve is this nerve that extends down coming from the C5, C6, and C7 roots.
The way I remember that is “C5, 6, 7 raise your wings up to heaven! C5, 6, 7 raise your wings up to heaven!” In order to fly, in order to raise your wings up to heaven, you have to have upward rotation of the scapula that happens with the help of serratus anterior which, now we know long thoracic nerve coming from “C5, 6, 7 raise your wings up to heaven!”
Makes sense, right? You can imagine flying up to the heavens, and when you reach up there eating some salt. Maybe that’s going to help you remember it. But, very simple, very easy to remember.
So, let’s review. Quiz ourselves. We have pectoralis major that gets innervated by the lateral and medial pectoral nerves. The lateral pectoral nerve from the lateral cord, and the medial pectoral nerve from the medial cord.
Then, there’s pectoralis minor which gets innervated by only the medial pectoral nerve.
We have subclavius muscle which gets innervated by the nerve to subclavius. Lastly, we have the salt one, the one that tastes good, serratus anterior innervated by the long thoracic nerve.
That’s pretty much it for this video. If you’re enjoying the videos, if you enjoyed this one, make sure to click on the ‘like’ button right below if you’re on YouTube and you can subscribe by clicking on the button right above that says ‘Subscribe.’
But, most of all, make sure to check out the website at interactive-biology.com for more Biology videos and other resources to help make Biology fun. This is Leslie Samuel. That’s it for this video and I’ll see you in the next one.