STRUCTURE AND POSITION :

•         Infraspinatus is a triangular muscle. It is present at the back of the Scapula.
•         It occupies the Infraspinatus Fossa of the Scapula posteriorly.
•         It is usually found fused with the Teres Minor.

ATTACHMENTS :

Infraspinatus Muscle has an origin and an insertion as follows.

•         Origin : Infraspinatus Muscle arises from the Medial aspect of the Infraspinatus fossa.
•         It runs horizontally and laterally towards the Shoulder Joint.
•         Insertion : Infraspinatus Muscle gets inserted into the Greater Tubercle of the Humerus at its middle aspect.

BLOOD SUPPLY :

Infraspinatus Muscle receives its blood from the Suprascapular and Circumflex Scapular Artery.

NERVE SUPPLY :

Infraspinatus Muscle is innervated by Suprascapular Nerve.

ACTION :

Infraspinatus Muscle rotates the Humerus externally. It also stabilizes the Shoulder Joint being a part of the Rotator Cuff Muscles. It stabilizes humerus during abduction.