Page 425 - The Veterinary Care of the Horse

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VetBooks.ir CONDITIONS AFFECTING BONE

PERIOSTITIS

Periostitis is inflammation of the periosteum which is the thin membrane that covers bone. It
may be thought of as a protective ‘clingfilm’ wrapper around the bone. The periosteum is
composed of two layers:

• an outer fibrous layer

• an inner cellular layer containing blood vessels and cells that can differentiate into
osteoblasts. These cells are able to produce new bone.

The periosteum is important for:
• attachment of tendons and ligaments to bone

• nutrition of bone

• growth of young bone

• repair of bone fractures.

Causes

The periosteum can become inflamed following:

• repeated stress

• a direct blow

• tearing of the attached ligaments.

The resultant haemorrhage lifts the periosteum away from the bone and this stimulates the
osteoblasts to produce new bone.

Clinical signs

A tender, bony swelling develops. This is often accompanied by heat and inflammation of the

surrounding soft tissue. If the affected area is pressed, the horse will often react by moving