Scythian Movement

Horses have a tremendous range of motion from their ears to the top of their tail. Their shoulders connect to their spine via muscle (no collar bones). They have 7 cervical vertebrae, 18 Thoracic vertebrae, 5-6 lumbar vertebrae, 5 sacral vertebrae (fused), and an average of 18 caudal vertebrae (range 15-25) (Dyce et al, 2016). The sacrum is fused and does not flex. All the others have a joint with some degree of flex often in multiple planes.

The dark dorsal stripe on the mare pictured below demonstrates how much flex is possible. The black marking is part of the mare's coloring and runs from the black mane to the black tail across the top of her spine. This handy marker shows the spine flexing in both the dorso-ventral (back to belly) and lateral (side to side) axis. The combination of many vertebrae each moving a little in preferred directions creates a dramatic twist in the back.

The Scythian examples are absolutely stylized, but the artists could have drawn inspiration from naturally expressed equine movement.