Q: What is topline?
A: To put it simply, a horse’s topline are the muscles that support the spine from the neck all the way to the hindquarters. The topline of a horse stretches along the spinal column from the end of the neck at the wither area, down the back and loin. Three main muscle groups surround each side of the spine. These are the longissimus dorsi, which is attached to the pelvis, the entire thoracic spine and the last four cervical vertebrae. The latissimus dorsi attaches the upper and mid back vertebrae to the lower lumbar vertebrae. The thoracic trapezius attaches the neck and mid-back vertebrae to the shoulder blade. These muscles are important as they play a role in how a horse performs, looks and feels.
In a horse with a well-developed topline the neck should transition smoothly into the shoulders, with no angular spaces around the withers. The spine should then be surrounded by toned muscles, along its length down into the croup. Topline is affected by conformation, nutrition, core strength, saddle fit, age and lameness issues.