Horse Anatomy: The Back 1/2

The strength and structure of the back of a horse are critical for the usefulness of the animal. Since a horse is used for a variety of activities, it therefore is necessary for the user of the animal to understand the strengths and weaknesses that can occur with a particular horse. The back is a complex design of bone, muscle, tendons and ligaments that all work together to allow a horse to support the weight of a rider.

The shape of a horse’s back can vary from horse to horse and it can change on an individual horse over the years, as the horse ages. The ‘topline’ of the back is the upper curvature of the withers through the bac and to the loins whereas the ‘underline’ is the length of belly from the elbow to the flank. Both lines work together, to enable the horse to move flexibly. The abdominal muscles where the underline is, can provide tremendous support to the back when well conditioned. A long ‘underline’ in relation to a shorter ‘topline’ is ideal for riding activities.

The average horse can carry up to approximately 25% of its body weight. This also depends on body structure or the conformation and the physical condition of the horse. In other words, a horse with well-developed abdominal and back muscles, will be able to carry more weight for a longer time than one that is not in shape

A ‘roach’ back and a ‘sway’ back are two primary flaws in back conformation. A ‘roach’ back or a straight back on a horse is when there is insufficient curvature of the spine as is not as common as a ‘sway’ back. The ‘sway back is when there is too much curvature. Either conformation can be distressful to a horse, but can also be if not overcome than aided, with proper attention.

The ideal length of a horse’s back is one third of the entire length of the body. A long backed horse is when the length from the peak of the withers to the point of the hip exceeds a third of the overall body length or from the point of the shoulder to the point of the buttock, excluding the head and neck. Whereas, a short back is less that one third of the body length.

An example of a long backed horse might be that of a ‘gaited’ horse, such as an American Saddlebred or a Tennessee Walker, though not all long backs are ‘gaited’. The advantage of riding these types of horses is that the back is flexible, making the back flatter, quieter and an overall smoother ride. The disadvantage is that it is difficult for the horse to round his back up for tight quick maneuvers. An example of a short back could be Arabians, Morgans or the American Quarter Horse. The advantage to a short back is that the horse is quick, agile and strong, able to change direction with ease. However, a short back is usually less flexible and could lead to spinal arthritis.

In determining the conformation of the back of a horse, a rider can decide if a particular horse will suit him or her. It will tell the rider whether or not the horse in question will suffer from exposure to the work determined by that rider. If an animal is showing signs of back pain a veterinarian experienced in large animal care or an experienced horse owner can palpate the back of a horse to pinpoint sources of pain and from there, assess the most likely cause of the pain.