Cross sections of the equine thorax cut through the body at the level of the withers. The bones and muscles are labeled. In View A, muscles are in various shades of red and orange, loose connective tissue is gray, bones are yellow, nuchal ligament is gold, scapular cartilages are green and the DSL is in blue. View B is a simplification, with bones in dark brown for emphasis, and only those muscles that attach to the DSL are colored. Note how the forelimbs hang off the DSL. The plane where “bubble wrap” fascia is found is marked.

Farrier Takeaways

• The shoulder to thorax junction constitutes the upper end of the forelimb reciprocating system.
• Horses lack collar bones and there is no socketed joint between the rib cage and forelimb.
• The dorso-scapular ligament (DSL) anchors the top of the forelimb, while the serratus ventralis and pectoral muscles form the thoracic sling. Together they substitute for a socketed joint.