We now move on to the six intrinsic shoulder muscles. Watch and learn as Leslie enumerates and locates each of them in the body.
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 to be answering a question, and that question is, “What are the six intrinsic shoulder muscles?”
By intrinsic shoulder muscles we mean the muscles that originate on the scapula and then, they insert on the humerus, so they’re connecting the scapula to the humerus. So, what are they?
Muscle number one, that would be the deltoideus muscle or the deltoid muscle. You can see that here in the picture and we’re going to talk about that in the next video, the details, the origins, the insertions, and the actions. We’re going to talk about that in the next video. But, for right now, we’re just listing them out.
Muscle number one, deltoideus.
Muscle number two, supraspinatus, and you can see that coming from the supraspinous fossa and going to the humerus and we’ll talk about those details. But, supraspinatus is muscle number two.
Muscle number three would be infraspinatus. You can see that muscle here. Then, we have teres minor. We also have teres major, and that’s going to be inferior to teres minor. Then, we have subscapularis. That’s on the anterior side of the scapula.
Those are the intrinsic muscles. So just as a review, we have:
- Teres Minor
- Teres Major
That’s pretty much it for this video, and as usual, if you want more videos like this and other resources to help make Biology fun, you know what to do. Head on over to the website at Interactive-Biology.com.
This is Leslie Samuel. That’s all for this one and I’ll see you on the next.
|Deltoideus||(exact opposite of the insertion of trapezius muscle)|
Inferior margin of the spine of the scapula, lateral margin of the acromion, and lateral third of the anterior clavicle.
|Deltoid tuberosity of humerus.||Axillary nerve (C5, C6)||Middle portion: Abducts arm at shoulder.
Posterior portion: laterally rotates and extends arm at shoulder.
|Suprasipnatus||Supraspinous fossa of scapula.||Superior aspect of greater tubercle of humerus.||Suprascapular nerve (C5)||Helps deltoid abduct arm at shoulder by drawing humerus toward glenoid fossa of scapula.|
|Infraspinatus||Infraspinous fossa.||Middle facet of the greater tubercle of the humerus.||Suprascapular nerve.||External rotation|
|Teres Minor||Upper 2/3 of the posterior surface of the lateral border of the scapula.||Lower facet of the greater tubercle of the humerus.||Axillary nerve.||External rotation and adduction of the humerus.|
|Teres Major||Lower lateral border and inferior angle of scapula.||Medial lip of intertubercular (bicipital) groove of anterior humerus.||Lower subscapular nerve (C5, C6)||Adducts, medially rotates, and extends arm at shoulder.|
|Subscapularis||Subscapular fossa of scapula.||Lesser tubercle of humerus.||Upper and lower subscapular nerves (C5, C6).||Medially rotates arm at shoulder.|