Infraspinatus

Infraspinatus

Infraspinatus

Infraspinatus Tendon

Infraspinatus Tendon

Muscle Origin

Infraspinous fossa of scapula to greater tubercle of humerus.

Infraspinous fossa of the scapula. The Infraspinatus muscle attaches medially to the infraspinous fossa of the scapula and laterally to the middle facet of the greater tubercle of the humerus. The muscle arises by fleshy fibers from the medial two-thirds of the infraspinatous fossa, and by tendinous fibers from the ridges on its surface; it also arises from the infraspinatous fascia which covers it, and separates it from the teres major and teres minor.

Insertion

Middle facet of greater tubercle of the humerus.

The infraspinatus attaches to the middle facet of the greater tubercle.

Action

Laterally rotates arm at shoulder.

It rotates the head of the humerus laterally and assists in stabilizing the humerus in the glenoid cavity. American Academy of Manual Medicine

The infraspinatus is the main external rotator of the shoulder. When the arm is fixed, it abducts the inferior angle of the scapula. Its synergists are teres minor and the deltoid. The infraspinatus and teres minor rotate the head of the humerus outward (external, or lateral, rotation); they also assist in carrying the arm backward. Additionally, the infraspinatus reinforces the capsule of the shoulder joint. Wiki

Innervation – Nerve control

Suprascapular nerve.

The suprascapular nerve innervates the supraspinatus and infraspinatus muscles. These muscles function to abduct and laterally rotate the arm, respectively. Wiki

Artery

Suprascapular and circumflex scapular arteries.

The suprascapular artery, also known as the transverse scapular artery, is a branch of the thyrocervical trunk, while the circumflex scapular artery (scapular circumflex artery, dorsalis scapulae artery) is a branch of the subscapular artery and part of the scapular anastomoses. Wiki

Antagonist muscles

Pectoralis major, Pectoralis minor, Subclavius, Serratus anterior, Latissimus dorsi, Trapezius, Rhomboid major, Rhomboid minor, Levator scapulae.

Pictures of muscles

 

Trigger Point Referrals

 

Stretching description

 

Exercises

 

Injuries

 

Treatment

 

Additional Resources
Sports Lab
Wiki
American Academy of Manual Medicine

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