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Location & Overview
The supraspinatus is a relatively small muscle located in the upper shoulder region. The supraspinatus muscle is one of the four rotator cuff muscles, which also include the infraspinatus, teres minor, and subscapularis muscles. A useful mnemonic to remember these muscles is “SITS”.[1,2]
Occupying the supraspinous fossa of the scapula, above the spine of the scapula, the supraspinatus muscle is the most superiorly positioned rotator cuff muscle. The supraspinatus tendon extends laterally, passing beneath the acromion process and over the head of the humerus to insert onto the superior facet of the greater tubercle of the humerus. Because the supraspinatus travels under the acromion, this can make it vulnerable to impingement. The space under the acromion is called the ‘subacromial space’. As part of the dynamic stabilization system for the glenohumeral joint, the supraspinatus contributes significantly to shoulder stability and motion.[2,3,4]
Common pathologies related to the supraspinatus muscle include rotator cuff tears, impingement syndromes, and tendinitis, which typically present as shoulder pain and restricted range of motion. Strengthening exercises, physical therapy, and surgical interventions are among the treatment options for these conditions.[2,3,4]




Origin & Insertion
The supraspinatus originates from the supraspinous fossa. The supraspinous fossa is a shallow depression found on the dorsal aspect of the scapula, located superior to the spine of the scapula. After originating here, its tendon extends laterally, passing underneath the acromion process. The acromion process is a bony extension of the scapula that forms the highest point of the shoulder on its lateral side.[5,2,3,4]
The insertion of the supraspinatus muscle is the superior facet of the greater tubercle of the humerus. The greater tubercle is a large, bony prominence of the humerus, located on the lateral and proximal part of the bone. The superior facet refers to the topmost part of this bony landmark, where the supraspinatus tendon attaches.[5,2,3,4]

Action & Function
The supraspinatus contributes to abduction of the humerus, allowing for movements such as lifting the arm to the side.[2,1,4] It also contributes weakly to the lateral (external) rotation of the humerus.[6,5,4] Furthermore, as part of the rotator cuff, the supraspinatus provides stability to the head of the humerus on the shallow glenoid fossa during joint movements and works with the deltoid muscle to prevent the downward displacement of the humeral head.[7]


Innervation
The supraspinatus is innervated by the suprascapular nerve, which originates from the upper trunk of the brachial plexus, with nerve roots from C5 and C6. This nerve enables communication between the supraspinatus and the central nervous system. The suprascapular nerve also innervates the nearby infraspinatus muscle.[2,1]


Blood Supply
The supraspinatus receives its blood supply mainly from the suprascapular and dorsal scapular arteries, which are branches of the thyrocervical trunk and the third part of the subclavian artery, respectively. These arteries provide the muscle with essential nutrients and oxygen for its optimal functioning.[4,8]
References
- [1] Standring S. (2015). Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 41st Edn. Amsterdam: Elsevier.
- [2] Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincott Williams & Wilkins; 2017.
- [3] Maruvada S, Madrazo-Ibarra A, Varacallo M. Anatomy, Rotator Cuff. (Updated 2023 Mar 27). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441844/
- [4] Jeno SH, Munjal A, Schindler GS. Anatomy, Shoulder and Upper Limb, Arm Supraspinatus Muscle. (Updated 2022 Aug 30). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537202/
- [5] Wu JG, Bordoni B. Anatomy, Shoulder and Upper Limb, Scapulohumeral Muscles. (Updated 2023 May 19). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546633/
- [6] Langenderfer JE, Patthanacharoenphon C, Carpenter JE, Hughes RE. Variation in external rotation moment arms among subregions of supraspinatus, infraspinatus, and teres minor muscles. J Orthop Res. 2006 Aug;24(8):1737-44. doi: 10.1002/jor.20188. PMID: 16779813; PMCID: PMC1551907.
- [7] McCausland C, Sawyer E, Eovaldi BJ, et al. Anatomy, Shoulder and Upper Limb, Shoulder Muscles. (Updated 2022 Aug 8). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534836/
- [8] de la Garza O, Lierse W, Steiner D. Anatomical study of the blood supply in the human shoulder region. Acta Anat (Basel). 1992;145(4):412-5.
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