Muscle Anatomy: What is the Infraspinatus Muscle?

May 23, 2024

The Infraspinatus muscle (on bottom portion of your shoulder blade) is one of your rotator cuff muscles. It originates from the medial two-thirds of the infraspinous fossa of the scapula, and the internal surface of the infraspinous fascia. It inserts onto the middle facet of the greater tubercle of the humerus. It externally rotates the humerus (upper arm bone) and stabilizes your shoulder joint.

*The origin of a muscle is the most fixed attachment point.

**The insertion of a muscle is the most moveable attachment point.

Chronic overloading or injury of this muscle can create trigger points which in turn may refer pain into your upper arm and even radiate down into your hand. Well placed trigger point injections (administered by your physician), dry needling (administered by your Acupuncturist), or trigger point therapy combined with muscle energy techniques can significantly reduce pain and tension in this muscle and improve your mobility.

In the image above, the areas of muscle marked with an X are where trigger points (“knotted” areas of hyperirritable muscle) occur in the Infraspinatus muscle. The areas of red are where the trigger points often refer pain. As Ida Rolf stated, “Where it is it ain’t!”