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.

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.