Teres Minor

Description[edit | edit source]

Teres Minor is a narrow muscle which liesbelow infraspinatus, above teres major and triceps brachii, and deep to deltoid. It is one of the four muscles which comprise the Rotator Cuff.

Teres minor muscle.png

Origin[edit | edit source]

The upper two-thirds of the lateral border of the posterior surface of the scapula.[1]

Insertion[edit | edit source]

The upper fibres end in a tendon which inserts into the inferior facet of the greater tubercle of the humerus. The lower fibres insert into the humerus directly below the inferior facet of the greater tubercle of the humerus.[1]

Nerve Supply[edit | edit source]

The axillary nerve (roots C5, C6) from the posterior cord of the brachial plexus.[2]

Blood Supply[edit | edit source]

The subscapular artery ,the circumflex scapular artery and the posterior circumflex humeral artery.[2]

The subscapular artery and the posterior circumflex humeral artery arise from the third, most distal portion of the axillary artery. [2]

Action[edit | edit source]

  • Teres Minor, along with Infraspinatus, primarily produces external rotation of the shoulder joint.[2]
  • It assists in adduction and extension of the shoulder.[3]
  • When the humerus is stabilized, abducts the inferior angle of the scapula.[3]

Function[edit | edit source]

In concert with the other rotator cuff muscles, Teres Minor is instrumental in providing stability to the shoulder joint, and helps to hold the humeral head in the glenoid cavity of the scapula.[2]

Assessment: Hornblower’s sign[edit | edit source]

Hornblower's sign can be used to evaluate the teres minor for injuries, particularly tears. The patient's arm should be 90 degrees in the scapular plane, with the elbow flexed. The patient will then externally rotate against resistance, attempting to form a "field goal" sign. The test is positive if the patient is unable to rotate their shoulder externally, indicating minor pathology.[4]

[5]

Resources[edit | edit source]

[6]

[7]

References[edit | edit source]

  1. 1.0 1.1 Gray, Henry. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918; Bartleby.com, 2000.
  2. 2.0 2.1 2.2 2.3 2.4 Juneja P, Hubbard JB. Anatomy, shoulder and upper limb, arm Teres minor muscle. StatPearls Publishing; 2023.
  3. 3.0 3.1 Editor DT. Teres Minor : Wheeless’ Textbook of Orthopaedics [Internet]. Wheeless’ Textbook of Orthopaedics. 2020
  4. D’Ambrosi R, Ragone V, Comaschi G, Usuelli FG, Ursino N. Retears and complication rates after arthroscopic rotator cuff repair with scaffolds: a systematic review. Cell Tissue Bank [Internet]. 2019;20(1):1–10. https://pubmed.ncbi.nlm.nih.gov/30673902/
  5. CRTechnologies. Hornblower’s Sign Test (CR) [Internet]. Youtube; 2011. Available from: https://www.youtube.com/watch?v=w6bfFQ0Q6WA
  6. Kenhub-Learn Human Anatomy. Teres Minor Muscle - Origins & Action - Human Anatomy | Kenhub [Internet]. Youtube; 2014.
  7. AnatomyZone. Teres Minor | Muscle Anatomy [Internet]. Youtube; 2018