Most horses have 18 ribs. Arabians and some crosses have 17 ribs. Adult horse ribs are very heavy, strong bones that are rarely fractured and even more rarely diagnosed as fractured. A large impact to the rib cage is necessary to cause fracture. This can happen in a fall, a severe kick from another horse, or collision with a moving object (car or other horse), or heavy stationary objects.

(Note: Foals sometimes fracture their ribs in the birthing process, and this is discussed in a separate diagnosis record "Foal or Newborn, Fractured or Broken Ribs.")

Signs of fractured ribs are swelling, heat, and pain in the affected area, and sometimes reluctance to walk. In some cases, crackling or crunching can be felt when the area is pressed. Since other conditions can result in most of these signs too, definitive diagnosis of a rib fracture requires radiography (x-ray) or ultrasound.

Occasionally horses that have sustained an injury to the rib cage area may also be depressed, off feed and/or breath rapidly. These horses require rapid veterinary care. In rare cases, a fractured rib may splinter and the broken end pay penetrate deeper into the chest or abdomen, lacerating internal structures like lung, liver, spleen and intestine.

Horses that suffer penetration into the chest and get a pneumothorax (collapsed lung) will usually have rapid, labored breathing, flared nostrils and appear distressed. Ribs that are fractured in multiple places may cause a condition known as "Flail Chest", in which the relatively rigid chest wall moves abnormally, disrupting normal respiration.

Treatment is usually conservative, time and rest is usually all that is needed. There are options for surgically repairing fractured ribs, but in most cases this is not necessary. For uncomplicated cases, a permanent bump may be felt where the fracture bridge (callus) formed.

It may take several months for fractured ribs to heal to the point that saddling and riding can resume.