A lower jaw fracture is technically known as a mandibular fracture. A maxillary fracture is a fracture of your dog’s upper jaw. Both mandibular and maxillary fractures are more common in dogs than humans because most dogs’ jaws protrude further from their faces than do most human jaws.

Mandibular fractures, like maxillary fractures, are classified as either simple or comminuted and as either open or closed. A simple fracture means the mandibular – or lower jaw – has broken in only two pieces, whereas a comminuted fracture means that the bone has fractured in more than two pieces. An open fracture means that the bone has been exposed, as opposed to a closed fracture where the bone is not visible. Because the mandibular is relatively close to the surface with little tissue covering it, most fractures are open fractures. Open fractures carry with them the danger of infection.

Physical signs of a mandibular fracture in your dog include excessive drooling, a swollen jaw, broken teeth, pain during eating and chewing, and a jaw that hangs open or is unable to close. If the fracture is very severe or painful to your dog, he can go into shock from trauma or blood loss.

Mandibular fractures are usually the result of trauma to the head or jaw. Car accidents and falls are examples of common traumas that can result in mandibular fractures. Mandibular fractures can also be caused by bone disease, periodontal disease, malnourishment, kidney disease, exocrine diseases, and by mouth and jaw tumors.

Your veterinarian will do a physical exam of your dog and likely take x-rays to confirm the diagnosis. In the event that the fracture was caused by trauma, your veterinarian will also look for neurological damage and damage to other organs and bones. Other diagnostic imaging techniques such as CT-scans can further assess mandibular fractures.