Broken Jaw

What Is It?

When a bone breaks or cracks, the injury is called a fracture. Jaw fractures are the third most common type of facial fractures, after fractures of the nose and cheekbone. They can be caused by many different types of impacts to the lower face, including:

• An accidental fall, especially in children who are playing and in adults who faint
• Hitting the dashboard during a car accident
• A fall from a motorcycle or bicycle
• A fall or collision during contact sports
• A punch to the jaw

The jaw bone is also called the mandible. It is a long bone that includes your chin and angles up toward your ear on both sides of your face. On each side, the end of the jawbone is rounded like a ball. This "ball," called the condyle, is the part of the jaw joint right in front of your ear; it lets you open and close your mouth. The jaw joint is also called the temporomandibular joint or TMJ.

A fracture can happen anywhere along the jawbone. In more than 50 percent of cases, the jaw fractures in at least two places — a "direct" fracture where the jaw was hit and an "indirect" fracture somewhere else along the jaw. Most often, this second fracture is near one of the ends of the mandible, close to the jaw joint. The second fracture occurs when the force of impact travels upward along the jaw and snaps the relatively thin part of the jawbone just below the ear.

Fractures of the condyles are the most common type of jaw fracture in children. They usually occur when a child falls and strikes his or her chin against the ground or some other hard surface. In teenagers and young adults, jaw fractures more commonly occur on the side of the face nearer the chin because this area is often struck during fights or attacks.

An impact with a dashboard during a car accident can fracture any part of the jaw, including the condyles. The force of the impact can dislodge teeth and cause fragments of the broken jaw to pierce the gum or damage nearby blood vessels and nerves.

Symptoms

Symptoms of a broken jaw can include:

• Bruising, swelling and tenderness along your jaw or below your ear
• The feeling that your teeth don't fit together properly or that your bite is "off"
• Improperly aligned teeth
• Missing teeth or loose teeth
• Swelling or a bruised area in the gum over your jawbone
• Difficulty opening your mouth
• Pain in your jaw joint
• Numbness in your lower lip or chin — a possible sign of nerve damage related to the fracture

When a young child falls on his or her jaw, a deep cut may occur along with a fractured jaw. Parents or other adults may focus on stopping the bleeding and not consider signs of a jaw fracture. If the child is too young to describe some symptoms, the jaw fracture may not be discovered until the child is older and complains of bite problems (malocclusion).