Page 567 - The Veterinary Care of the Horse

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Figure 12.21 Impingement and overriding of the dorsal spinous processes

Causes

• The condition may be congenital. Horses with short backs are most likely to be affected.

• Many horses with impinging DSPs are asymptomatic. The onset of pain may be triggered

by a fall.
• Horses that jump and do fast work tend to experience problems as the DSPs of the

middle and caudal thoracic regions may impinge when the horse lands after a fence or
extends its back at gallop.

• Dressage horses performing lateral work are susceptible.

• Impingement may occur as the horse ages and its back becomes more hollow.

Clinical signs

There are many horses with impingement and remodelling of their DSPs that do not appear

to have back pain. When the DSPs are a source of pain, the symptoms are very variable.
They tend to develop gradually as the horse’s work becomes more advanced and physically

demanding. Possible symptoms include:
• muscle guarding or spasm

• resentment of being brushed, rugged up, saddled, mounted or ridden

• change of temperament and loss of enthusiasm for work