Teres Minor Muscle – Attachments, Actions & Innervation

Author: Scott A. Sheffield MS

Last update:

Teres minor is one of four muscles that comprise what’s called the rotator cuff.

It’s narrow and elongated in shape and sometimes may be fused with infraspinatus. The main function of the teres minor muscle is to stabilize the humerus in the glenoid fossa when the shoulder moves.

image descriptionTeres Minor Muscle

Image showing superficial muscles of the back and posterior shoulder and arm. Teres minor highlighted. Labelled muscles: trapezius, deltoid, infraspinatus, teres major, triceps brachii (lateral head), triceps brachii (long head), latissimus dorsi.
Image showing superficial muscles of the back and posterior shoulder and arm. Teres minor highlighted. Labelled muscles: supraspinatus, infraspinatus, teres major, teres minor, triceps brachii (lateral head), triceps brachii (long head).
Image showing posterior view of the back, shoulder and arm. Teres minor labelled.
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image descriptionAttachments of Teres Minor :Origin & Insertion

Origin: (proximal attachment)
a. Middle part of the lateral (axillary) border of the scapula.

Insertion: (distal attachment)
a. Inferior aspect of greater tubercle of humerus.

Learn teres minor anatomy even faster thanks to this handy upper limb muscle anatomy reference chart.

Image showing superficial muscles of the back and posterior shoulder and arm. Teres minor highlighted. Labelled muscles: trapezius, deltoid, infraspinatus, teres major, triceps brachii (lateral head), triceps brachii (long head), latissimus dorsi.
Image showing superficial muscles of the back and posterior shoulder and arm. Teres minor highlighted. Labelled muscles: supraspinatus, infraspinatus, teres major, teres minor, triceps brachii (lateral head), triceps brachii (long head).
Image showing posterior view of the back, shoulder and arm. Teres minor labelled.
Image showing posterior view of the back, shoulder and arm. Origin and insertion of teres minor labelled.
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Actions of Teres Minor:

a.   image descriptionLaterally rotates the arm at the shoulder (glenohumeral) joint.

b.  Weakly image descriptionadducts the arm at the shoulder (glenohumeral) joint.

c. Helps stablize the shoulder by drawing the humerus toward the glenoid fossa of the scapula.

Innervation of Teres Minor:

image descriptionNerve to the muscle:
a. Axillary nerve.

image descriptionNerve roots:
a. C5 and C6.

Image showing a posterior view of the brachial plexus and terminal branches, axillary nerve labelled.
Image showing the brachial plexus and the roots of the axillary nerve
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Ever wondered what the 10 most difficult to pronounce upper limb muscles are? Find it out in this video:

An Overview of the Posterior Muscles of the Arm:

Test yourself image of posterior view of back and right arm. No labels.
Test yourself image of posterior view of back and right arm. Muscles labelled: trapezius, deltoid, teres major, triceps brachii (lateral head), triceps brachii (long head), latissimus dorsi, extensor carpi radials longus, extensor carpi ulnaris.
Test yourself image of posterior view of back and right arm. Muscles labelled: splenius capitis, rhomboid minor, deltoid, rhomboid major, teres major, triceps brachii (lateral head), triceps brachii (long head), serratus posterior inferior, extensor carpi radials longus, extensor carpi ulnaris.
Test yourself image of posterior view of back and right arm. Muscles labelled: splenius capitis, serratus posterior superior, supraspinatus, infraspinatus, teres minor, teres major, triceps brachii (lateral head), triceps brachii (long head), serratus posterior inferior, extensor carpi radials longus.
Test yourself image of posterior view of back and right arm. Muscles labelled: splenius capitis, splenius crevicis, supraspinatus, infraspinatus, teres minor, teres major, triceps brachii (lateral head), triceps brachii (long head), erector spinae muscles, external oblique, internal oblique.
Test yourself image of posterior view of back and right arm. Muscles labelled: semispinalis capitis, elevator scapulae, supraspinatus, infraspinatus, teres minor, teres major, triceps brachii (lateral head), triceps brachii (long head), erector spinae muscles, external oblique, internal oblique.
Test yourself image of posterior view of back and right arm. Muscles labelled: supraspinatus, infraspinatus, teres minor, teres major, triceps brachii (lateral head), triceps brachii (long head).
Test yourself image of posterior view of back and right arm. Muscles labelled: supraspinatus, infraspinatus, teres minor, teres major.
Test yourself image of posterior view of back and right arm. Muscles labelled: teres minor.
Test yourself image of posterior view of back and right arm. Origin and insertion of teres minor labelled.
Test yourself image of skeleton of posterior view of back and right arm.
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