top of page

It’s Not Always the Hocks! Check out the equine SI Joint

Horses that are sore in the hindquarters can be difficult to diagnose. The problem might be found in the last place you look – the sacroiliac joint.


By Andria Massie, Equine Physiotherapist



Your horse is off. You can feel it. He doesn't want to go forward. The canter isn't right. He isn’t backing up properly. Can’t or won’t hold his hind leg up for the farrier, is reluctant or refuses to pick up legs over cavaletti and upward gait transitions seem difficult. Before you call out the vet you ask your friends, your trainer, your chiropractor, your farrier, EVERYONE to see if they see what you see. Overwhelmingly you hear, “it’s the hocks, gotta inject the hocks.” Sound familiar? I’d like you to hold up before you run to Dr. Google, take a minute and consider the SI joint.


A horse’s sacroiliac (SI) joint is defined as the intersection of the sacrum and the ilium. The sacrum consists of five vertebrae. These vertebrae completely solidify when a horse is around the age of five. When the vertebrae are fully solidified, they are able to bear a full-weight load.


📷 Trainer Magazine 2022

The sacroiliac joint connects a horse’s hindquarters to the rest of its body, playing an important role in permitting the use of the hindquarter's power and strength. This is a small and sensitive joint that is only held together by ligaments with no muscular structure directly connected to the area. Although the joint is highly sensitive, it must also be largely mobile in order to successfully transfer the power and strength created by the hindquarters to the forehand and back of a horse.

Overstraining, trauma, and improper training can cause restrictions and problems in the sacroiliac joint, which can notably affect the joint's structural integrity. If the joint’s structural integrity is indeed affected this will present through deficient muscle tones, particularly in the hindquarter region.


Signs of Deficient Muscles in a Horse’s Hindquarters


📷 VetkinTape

Signs of underdeveloped or deficient muscles include sharply ascending or descending croup and “dents” in the hindquarters sides. These signs should never be misinterpreted as a horse having an athletic build or ignored by handlers. When riding a horse with deficient muscles, these signs often present a way of riding that is heavier on the forehand and frequently points to a lack of exercise in younger horses.


Symptoms of a restriction in the SI Joint


Signs that can indicate the restriction of a horse’s SI joint include the following symptoms:

  • Limb lameness and difficulty maintaining the rhythm of a stride

  • Difficulties walking backward

  • Problems with the canter

  • The horse is unable to collect

  • A shortened stride

  • Problems with the spine

  • Less “push forward” or “go”


📷 Practical Horseman Magazine

These restrictions often result in a tilted sacroiliac joint. A tilted sacroiliac joint affects the movements and mechanics of a horse. An example of the presentation of a tilted sacroiliac joint can be described as a hunter's bump. This is a one-sided change in the pelvis positioning and results in the thigh bone migrating to an unnatural position, which also forces the hindquarter into an unnatural position. These issues must be corrected by the rest of the horse’s body, meaning the other areas are becoming overloaded by working in ways they are restricted from.


Rehabilitating a Horse’s SI Joint


Suspected sacroiliac joint problems in a horse should be brought to the attention of a veterinarian and equine physiotherapist with experience in these issues. These professionals can help handlers and owners get rid of any restrictions in the sacroiliac joint and restore it back to working order. The muscle groups surrounding the sacroiliac joint must be monitored during any restrictions and will require potential physiotherapy and care to treat muscle tension and damage. If the muscle groups are ignored and not treated, the work a veterinarian and equine physiotherapist has done to treat the damage and tension caused by the sacroiliac joint restriction will be rapidly undone.


Damage to the sacroiliac joints' sensitive structure can be prevented through the proper building of the muscle groups in a horse’s hindquarters and inner pelvis region as well as responsible riding. Ensuring your horse has a healthy, well-built, and strong muscular system can prevent a wide variety of issues within their skeletal system, including the sacroiliac joint.


Your veterinarian can determine if something needs to be done with your horse’s hocks. Definitely rule that out – but also consider the SI when dealing with hind end lameness and rehabilitation and ask for that to be evaluated too. My next article will discuss exercises to help stabilize and therapies to help mobilize your horse’s SI joint. You’ll be amazed at how you can help your horse by paying attention to the SI. Stay tuned! Have questions? I'd love to hear from you. Feel free to email me or call/text 541-636-1191.




bottom of page