This section is from the book "The Horse - Its Treatment In Health And Disease", by J. Wortley Axe. Also available from Amazon: The Horse. Its Treatment In Health And Disease.
A very small slender muscle situated at the back of the shoulder-joint.
Origin. - From the lower part of the scapula behind, immediately above the articular cavity.
Insertion. - Into the posterior part of the humerus just below its head, and into the capsular ligament of the joint.
Action. - It prevents the capsular ligament of the shoulder-joint from insinuating itself between the two bones.
 
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