Teres Minor Muscle
Origin: On the dorsal surface of the middle half of the lateral border of the scapula.
Insertion: The lowest facet of the greater tubercle of the humerus.
Actions: External rotation of the arm at the shoulder
Innervation: Axillary nerve (C5, C6).
Blood Supply: Circumflex scapular and posterior circumflex humeral arteries from the axillary artery.
Primary Actions of the Teres Minor
1. External rotation of the arm at the shoulder
Agonists:
- Infraspinatus
- Deltoid (posterior part)
Antagonists:
- Deltoid (anterior part)
- Subscapularis
- Pectoralis major
- Teres major
- Latissimus dorsi
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Secondary Actions of the Teres Minor
1. Assists with adduction of the arm at the shoulder
Agonists:
- Latissimus dorsi
- Pectoralis major
- Teres major
Antagonists:
- Deltoid (middle part)
- Supraspinatus
Coracobrachialis also assists with adduction of the arm at the shoulder.
1. Assists with depression of the humeral head
Agonists:
- Infraspinatus
- Subscapularis
Teres minor acts to clear the greater tubercle of the humerus under the acromial arch of the scapula.
Muscle Pain Information: The teres minor muscle contributes to pain in the back of the shoulder, and tingling in the fourth and fifth fingers.