08/26/2026
Have you ever noticed a horse with a very prominent or overdeveloped serratus muscle just behind/below the shoulder blade—right where the front of the saddle sits?
Bigger doesn’t always mean stronger.
The serratus ventralis is an important stabilizing muscle that helps suspend the horse’s trunk between the front limbs and supports movement of the shoulder blade. When the horse is moving correctly, it works as part of a much larger system.
But when there are saddle-fit problems, the body may start changing how it moves to avoid pressure or discomfort.
A saddle that pinches, sits too far forward, restricts the scapula, bridges, rocks, or concentrates pressure near the front of the tree can encourage a horse to brace and alter how the shoulder and trunk move. Over time, some muscles may become overworked and more prominent, while neighboring areas may become tight, sore, guarded, or even underdeveloped.
This is why I don't look at one muscle in isolation.
If I find an unusually prominent serratus, I also look for:
• Tenderness or tension behind the scapula
• Asymmetry from left to right
• Trapezius or latissimus tension
• Atrophy or hollows around the withers
• Restricted scapular movement
• Shortened stride or reluctance to reach forward
• Sensitivity where the front of the saddle/tree sits
• Changes in the horse's topline
Muscle development can tell a story about how a horse is using its body.
An enlarged serratus doesn't automatically mean the saddle is the problem, but paired with soreness, asymmetry, restricted movement, or other compensatory patterns, saddle fit should absolutely be part of the conversation.
Massage can help identify and address the muscular compensation, but if the source is saddle pressure or restriction, we also need to address the equipment creating it.
Treat the compensation. Find the cause. Help the horse move better. 🐴