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.
All the cervical roots of the brachial plexus contribute to form the nerve going to the subscapularis. After crossing the supra-spinatus some of the fibres pass between it and the subscapularis, and the rest are distributed to that muscle.
 
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