Teres Minor Anatomy

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.

Muscle Pain Information: The teres minor muscle contributes to pain in the back of the shoulder, and tingling in the fourth and fifth fingers.

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.