a spiral of pain. The horse moves in a different frame to avoid the pain caused by pressure points. The result is that other parts of the body get over worked or work improperly. A lot

of horses tolerate pain for quite a long time and only start to show obvious behavior once a significant amount of damage has already been caused.Wasted muscle tissue can be seen:on each side of the withers, which means that the trapezius, spinalis and/or rhomboid muscles have atrophied usually due to tree points of the

saddle that are too narrow
towards the end of the saddle panel since the saddle is not sitting level on the horse if it is too tight in front. This could tip the rider backwards which in turn increases the pressure under the cantle.
There are the rare cases that these kind of indentations show up due to fatty deposits. Heavier breeds or overweight horses can show indentations in the fat rather than a muscular atrophy. This should be further evaluated by a professional.