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Teres minor tendon (Distal)

The distal tendon of the teres minor is the terminal fibrous portion of the teres minor muscle — one of the four components of the rotator cuff. It extends from the muscle belly in the posterior scapular region to insert on the inferior facet of the greater tubercle of the humerus. This tendon plays a vital role in external rotation of the shoulder, posterior stabilization of the glenohumeral joint, and fine control of humeral head movement during arm elevation.

The teres minor tendon is smaller and more rounded than the other rotator cuff tendons and is closely associated with the infraspinatus tendon superiorly. Despite being the smallest rotator cuff component, it has significant functional importance, especially in maintaining shoulder joint integrity and stability.

Synonyms

  • Tendon of teres minor

  • Distal teres minor insertion

  • Inferior rotator cuff tendon

Origin, Course, and Insertion

  • Origin (muscle): Upper two-thirds of the dorsal surface of the lateral border of the scapula.

  • Course: Fibers run laterally and slightly upward, forming a small tendon that passes posterior to the shoulder joint capsule, blending partially with the posterior aspect of the infraspinatus tendon.

  • Insertion: Inferior facet of the greater tubercle of the humerus.

Tendon Attachments

  • Inserts on the inferior facet of the greater tubercle, immediately below the infraspinatus tendon insertion.

  • Some fibers blend with the posterior capsule of the glenohumeral joint, enhancing joint stability.

  • The tendon is rounded and compact, often separated from infraspinatus by a thin fat plane or subtle bursa.

Relations

  • Anteriorly: Posterior capsule of the shoulder joint and humeral head.

  • Posteriorly: Posterior deltoid muscle and subdeltoid bursa.

  • Superiorly: Infraspinatus tendon.

  • Inferiorly: Teres major tendon and long head of triceps brachii.

  • Laterally: Greater tubercle of humerus.

  • Medially: Teres minor muscle belly and lateral border of scapula.

Nerve Supply

  • Axillary nerve (C5–C6), branch of the posterior cord of the brachial plexus.

Function

  • External rotation of arm: Works with infraspinatus to rotate the humerus laterally.

  • Joint stabilization: Reinforces the posterior aspect of the glenohumeral capsule, preventing anterior translation of the humeral head.

  • Dynamic control: Assists in maintaining humeral head depression during arm elevation.

  • Synergistic action: Works with teres major (antagonistically) for coordinated shoulder movement.

Clinical Significance

  • Tendon tears: Isolated teres minor tears are rare; usually part of massive rotator cuff tears.

  • Atrophy: Denervation (often due to quadrangular space syndrome) causes fatty atrophy, visible on MRI.

  • Tendinopathy: Degenerative changes or impingement may cause posterior shoulder pain.

  • Quadrangular space syndrome: Compression of the axillary nerve and posterior humeral circumflex artery may affect teres minor function.

  • Imaging importance: MRI and CT are crucial for evaluating tendon integrity, atrophy, and post-surgical repair.

MRI Appearance

  • T1-weighted images:

    • Tendon: Low signal (dark linear band) inserting on the inferior facet of the greater tubercle.

    • Muscle belly: Intermediate signal with visible striations; fatty atrophy appears bright.

    • Marrow at insertion: Bright due to fatty bone marrow in adults.

    • Tear: Focal discontinuity or retraction with surrounding intermediate-to-bright signal.

  • T2-weighted images:

    • Tendon: Low signal; intact fibers appear as continuous dark bands.

    • Muscle: Intermediate-to-low signal, slightly darker than on T1.

    • Pathology: Tendinopathy or partial tear shows focal bright hyperintense areas within tendon substance.

    • Full-thickness tear: High-signal fluid gap at humeral insertion.

  • STIR:

    • Normal tendon and muscle: Intermediate-to-dark signal.

    • Pathology: Bright hyperintensity in tendon or myotendinous junction (edema, inflammation, partial tear).

    • Excellent for detecting acute injuries or peritendinous edema.

  • Proton Density Fat-Saturated (PD FS):

    • Normal tendon: Uniformly dark; sharply outlined insertion.

    • Tendinopathy: Focal bright signal in tendon substance or insertion.

    • Partial tear: Linear bright signal crossing tendon fibers without complete discontinuity.

    • Muscle atrophy: Reduced bulk, increased intramuscular fat (intermediate-to-bright signal).

  • T1 Fat-Sat Post-Contrast:

    • Normal tendon: Minimal or no enhancement.

    • Tendinitis or synovitis: Peritendinous enhancement along posterior capsule.

    • Tear repair or fibrosis: Heterogeneous enhancement around tendon stump.

    • Chronic atrophy: Little to no enhancement; fatty replacement remains bright on non-contrast T1.

CT Appearance

Non-Contrast CT:

  • Tendon: Not well visualized directly; appears as thin soft-tissue density inserting on humeral tubercle.

  • Bone: High attenuation; insertion site sometimes shows small enthesophytes in chronic stress.

  • Pathology: Reveals avulsion fragments, cortical irregularities, and calcific deposits (calcific tendinitis).

  • Muscle belly: Homogeneous soft-tissue density posterior to scapula.

Post-Contrast CT (standard):

  • Enhancement: Minimal for normal tendon; mild enhancement in inflammation or scarring.

  • Utility: Defines post-traumatic or postoperative soft-tissue thickening, and subtle pericapsular changes.

  • 3D reconstruction: Useful for pre-surgical planning in rotator cuff repair or tendon transfer.

MRI image

Teres Minor Tendon (distal) axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

MRI image

Teres minor tendon 3d mri 1mm image