30/06/2025
I love this series that Victory Equine Services do! So informative at the visual aids are great for better explanation
Muscle Monday - Longissimus Dorsi
The LONG-issimus dorsi is the longest muscle in the equine body. Although this muscle is the largest and most well know muscle of the back, it extends from the sacrum all the way up to the C4 vertebrae in the neck.
--- Function ---
The longissimus dorsi originates at the sacrum, ilium (pelvis), and along each lumbar and thoracic vertebrae. The longissimus dorsi inserts along the transverse processes of the vertebrae and the tubercles of ribs. Because the longissimus dorsi connects to the dorsal and transverse processes of all of the back vertebrae, it is the most powerful extensor muscle of the back.
- When both sides of the longissimus dorsi engage together, the spine is extended.
- When one side engages, the spine is flexed laterally.
- The longissimus dorsi also stabilizes the spinal column and transmits energy during movement.
This is one of the primary muscles to consider when fitting a saddle. Unlike the thin trapezius, which acts as more of a shoulder muscle, the longissimus dorsi is a large back muscle that can bear the weight of a saddle. I'll show a visual of this in the next post.