Teres minor tendon !
The teres minor tendon is the smallest rotator cuff tendon, at the back of the shoulder; it helps turn the arm outward.
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What it is
The smallest rotator cuff tendon, at the back of the shoulder; it can take over outward rotation when the infraspinatus is torn.
What it does
Helps turn the arm outward.
Key facts
- Attaches
- Teres minor to the inferior facet of the greater tubercle and the capsule below it
- Function
- Lateral rotation with the infraspinatus, more with the arm raised; holds the humeral head in the glenoid; supplied by the axillary nerve
- Tight in
- Medial rotation with the arm abducted
Relations
- Course
- From the lateral border of the scapula it runs up and laterally behind the shoulder joint to the lowest facet of the greater tubercle
- Above
- Infraspinatus tendon, often fused with it
- Below
- Quadrangular space (axillary nerve and posterior circumflex humeral artery) lateral to the long head of the triceps, triangular space (circumflex scapular artery) medial to it; the teres major below
- Superficial
- Posterior deltoid
- Deep
- Lower posterior shoulder capsule, which it reinforces
How to find it
Felt below the infraspinatus along the lateral border of the scapula with the arm slightly abducted; resisted lateral rotation makes it firm under the posterior deltoid. The tendon itself is small and is better seen on ultrasound.
Examination
- Patte test and hornblower sign: with the arm abducted to 90° and the elbow bent, weak lateral rotation, or the need to lift the elbow to bring the hand to the mouth, means the teres minor is torn or wasted
- Weak lateral rotation together with deltoid weakness and numbness over the lateral shoulder points to an axillary nerve injury rather than a tendon tear
On imaging
On sagittal MRI it is the lowest of the posterior cuff tendons; its bulk or fatty wasting is noted before repair of massive tears or reverse shoulder replacement. Isolated wasting suggests axillary nerve compression in the quadrangular space.
Common problems
- Rotator cuff tear, partial or full, from wear with age or from a fall; the most common cause of shoulder weakness.
- Tendinopathy and impingement: pain lifting the arm and at night.
- Calcific tendinitis: calcium deposits that cause sudden severe pain.
How it is diagnosed
Weakness and pain on cuff tests (for example the empty-can test). Ultrasound or MRI shows the tear size and muscle quality.
Treatment
- Physical therapy, pain medicines and sometimes injections, especially for partial and age-related tears.
- Arthroscopic rotator cuff repair with suture anchors for many full-thickness tears, especially recent ones in active people.
- Reverse shoulder replacement for large, irreparable tears with arthritis.
Clinical notes
- Quadrangular space syndrome: compression of the axillary nerve below it (fibrous bands, a cyst, hypertrophy in overhead athletes) wastes the teres minor and deltoid
- In massive cuff tears, a wasted teres minor means active lateral rotation is lost; a latissimus dorsi tendon transfer may be considered to restore it
- The plane between it and the infraspinatus gives access to the back of the shoulder joint; the axillary nerve lies just below it
Anatomical variants
- Its muscle may be fused with the infraspinatus
Test yourself
Think of the answer, then tap the question to see it.
Which nerve supplies the muscle of the teres minor tendon, unlike the other cuff muscles?
The axillary nerve; the other cuff muscles are supplied by the suprascapular and subscapular nerves.
What sign indicates loss of the teres minor in a massive cuff tear?
The hornblower sign: weak lateral rotation in 90° of abduction, so the elbow is lifted to bring the hand to the mouth.
Where does the teres minor tendon insert?
On the inferior facet of the greater tubercle and the capsule below it.
Which spaces does the teres minor muscle border, and what syndrome wastes it?
The upper border of the quadrangular and triangular spaces; quadrangular space syndrome compresses the axillary nerve, wasting teres minor and deltoid.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- tendo musculi teretis minoris TA2 2459
- Official Spanish (DeCS)
- Tendón del músculo redondo menor
- English (TA2)
- Teres minor tendon
Related
Sources: Terminologia Anatomica (TA2); Anatomy, Shoulder and Upper Limb, Teres Minor Muscle; Anatomy, Rotator Cuff.
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Representative model, for educational purposes only.
