Infraspinatus: Pain Pattern and Treatment
The infraspinatus covers the back of the shoulder blade and rotates the arm outward. Its documented pattern is the region’s defining mismatch: deep pain in the front of the shoulder, extending down the outer arm, sometimes to the thumb side of the hand, with a described component at the inner border of the shoulder blade.
Attachments and action
Origin: The infraspinous fossa on the posterior surface of the scapula.
Insertion: The middle facet of the greater tubercle of the humerus.
Action: External rotation of the shoulder and stabilization of the humeral head in the socket during arm movement, as part of the rotator cuff.
Where the pain is felt: Deep in the front of the shoulder, down the outside of the arm, into the upper back. The muscle sits on the shoulder blade; the pain sits in front. This mismatch is the region’s defining pattern.
Common causes: Reaching behind the body, throwing sports, swimming, repetitive overhead reaching, sleeping on the affected shoulder.
Patients say: “It hurts in the front, right here.” Trouble reaching into a back pocket or hooking a bra. Night pain lying on that side.
When to get evaluated: Inability to lift the arm after a fall, or a visible change in the shoulder’s shape, gets imaging before needling.
How this muscle is examined and treated
Examination tests reaching behind the back and resisted outward rotation, then maps the shoulder blade’s surface for the points that reproduce the front-of-shoulder pain. Needling the source on the back of the blade addresses pain the front-of-shoulder treatments miss. Assessment and treatment happen in the same visit.
Related conditions
Shoulder DysfunctionSports & Performance InjuriesTendinitis
This page is educational. It describes muscle referral patterns commonly associated with pain; it does not diagnose your condition. Individual patterns vary. For evaluation of your specific pain, see a licensed clinician. Seek immediate medical care for emergencies. Eugene Baek, L.Ac. · New Jersey License 25MZ00080600