Natural asymmetry in horses
Every horse is naturally crooked (asymmetrical) and either left- or right-handed in both the front and hind legs.The front legs carry more weight than the hind legs, and the horse has a natural bend in its body to either the left or the right.
Combined, this causes the horse’s weight to be unevenly distributed across its legs. This is not unique to horses; it also happens in dogs, for example. 
When we ride, it is crucial to do so in a way that corrects these asymmetries, as they can cause major issues for the horse. We achieve this through straightening (or rectification).
What are the symptoms of natural crookedness?
- The saddle slipping to the outside
- Striking off in the wrong canter lead
- Stumbling
- Disobedience
- Lameness
- Rearing
- Bucking
- Tension
- Falling over the outside shoulder
- Difficulty bending
- The hindquarters swinging out
- Developing a ewe neck (under-neck)
- Etc.