Teres Minor

backMusculus teres minor

The teres minor is a narrow strap along the outer edge of the shoulder blade that rotates the arm outward. It does the same job as the infraspinatus above it and is the smallest of the rotator cuff.

The teres minor runs along the outer edge of the shoulder blade, upward and outward to the back of the top of the arm bone, sitting just below the infraspinatus and just above the teres major. All three are neighbours on the same edge of the same bone.

It rotates the arm outward, exactly as the infraspinatus does, and holds the head of the arm bone down in the socket as the arm rises. Because their fibres run in nearly the same direction and their tendons blend into the same sleeve, there is no way to train one without the other and no reason to want to.

The thing worth remembering is the contrast with its neighbour below. Teres minor and teres major sit side by side, share most of a name, and do opposite things: minor rotates the arm outward and is part of the rotator cuff, major rotates it inward and is not. The one-word difference in their names conceals a complete reversal.

It also has a different nerve supply from the rest of the cuff — the axillary nerve, which it shares with the deltoid, rather than the suprascapular or subscapular nerves. A detail rather than a practical difference, but a real one.

Training notes

Everything that trains the infraspinatus trains the teres minor: side-lying external rotation, banded external rotation with the elbow tucked, cable external rotation. There is no separate movement and no benefit to looking for one.

Because it also assists in pulling the arm down and in, it contributes to pulldowns and rows in a small way — but that is assistance, not rotation, and does not train it in the way rotation work does.

As with the rest of the cuff, keep the load light and the elbow position honest. These are small muscles with short leverage, and adding weight past the point where the elbow stays at the ribs simply moves the work to the rear deltoid.

Anatomy

Origin
  • Upper two-thirds of the posterior surface of the lateral border of the scapula
Insertion
  • Inferior facet of the greater tubercle of the humerus
Actions
  • Externally rotates the humerus, turning the arm outward
  • Holds the head of the humerus down and into the socket
  • Assists adduction of the arm
Innervation
Axillary nerve (C5–C6)

Exercises

Antagonists

Synergists