Teres Minor Muscle Anatomy

The teres minor is a narrow, elongate muscle that is completely hidden by the deltoid and is often not clearly delineated from the infraspinatus. The teres minor works with the infraspinatus to rotate the arm laterally and assist in its adduction. The teres minor is most clearly distinguished from the infraspinatus by its nerve supply. The teres minor is supplied by the axillary nerve, whereas the infraspinatus is supplied by the suprascapular nerve.

Teres Minor Muscle Anatomy

Origin & Insertion

The teres minor represents one of the four muscles comprising the rotator cuff complex. This small, elongated muscle originates from the Superior part of the lateral border of the scapula and extends laterally to insert into the inferior facet of the greater tubercle of the humerus. Its position between the infraspinatus superiorly and teres major inferiorly creates important anatomical relationships that influence both its function and clinical presentation.

See Also: Rotator Cuff of the Shoulder

Innervation & Blood Supply

The teres minor receives its primary innervation from the axillary nerve (C5, C6), which courses through the quadrangular space. This anatomical arrangement creates a vulnerable point where nerve compression can occur.

The arterial supply primarily derives from the posterior circumflex humeral artery, with additional contributions from the circumflex scapular artery, creating a rich vascular network that supports muscle function and healing.

Function

The teres minor’s primary action involves external rotation of the humerus, working synergistically with the infraspinatus muscle. However, its role extends beyond simple rotation. During arm elevation, the muscle provides critical stabilization of the humeral head within the glenoid fossa, preventing superior migration that could lead to impingement syndromes.

Clinical Implications

In clinical practice, isolated teres minor pathology is relatively rare, but understanding its involvement in broader shoulder dysfunction remains crucial. Electromyographic studies have demonstrated that the muscle shows increased activity during throwing motions, particularly during the deceleration phase. This understanding has significant implications for rehabilitation protocols in athletic populations.

References & More

• Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 42nd Edition https://www.elsevier.com/books/grays-anatomy/standring/978-0-7020-7710-5
• Journal of Shoulder and Elbow Surgery https://www.jshoulderelbow.org/
• Clinical Anatomy of the Shoulder: An Atlas https://link.springer.com/book/10.1007/978-3-642-53956-5
• American Journal of Sports Medicine https://journals.sagepub.com/home/ajs
• Clinically Oriented Anatomy, 8th Edition https://www.lww.com/moore-clinically-oriented-anatomy
• Juneja P, Hubbard JB. Anatomy, Shoulder and Upper Limb, Arm Teres Minor Muscle. [Updated 2023 May 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: Pubmed