Equine Complex Vertebral Malformation (ECVM) — Part 1: What It Is and Why the Lower Neck Matters

The lower neck is more than a connection between head and body—it anchors muscles, nerves, and support structures that influence posture, balance, and movement throughout the horse.

Equine Complex Vertebral Malformation (ECVM) is a congenital condition involving abnormal development of the lower cervical vertebrae—most commonly C6 and C7, and sometimes the first rib. These structures form a critical junction between the neck, shoulders, and forehand, playing a major role in how a horse balances, moves, and performs.

The lower cervical spine serves as an anchor point for powerful muscles that influence shoulder motion and forelimb swing. It also houses nerve pathways supplying the forelimbs and supports the thoracic sling, which suspends the trunk between the front legs. When these vertebrae are malformed—whether through missing structures, asymmetry, or misplaced attachments—the effects can ripple through the entire body.

Horses with ECVM may struggle with posture and balance, show reduced neck flexibility, or experience limitations in shoulder freedom. Over time, these structural changes can contribute to discomfort, altered movement patterns, and declining performance.

Because ECVM is congenital, affected horses are born with these changes. However, the signs may not become obvious until training demands increase or compensatory patterns overwhelm the body’s ability to adapt. Understanding ECVM is the first step toward recognizing when a horse’s neck may be contributing to broader performance or soundness concerns.

Next: How ECVM may show up under saddle and in daily handling.