eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics

Fracture, Mandible

Author: Thomas Widell, MD, Vice Chairman, Assistant Professor, Department of Emergency Medicine, Rosalind Franklin School of Medicine/The Chicago Medical School, North Chicago, Illinois; Associate Residency Director, University of Chicago Emergency Medicine Program, Chicago, Illinois; Program Director Emergency Medical Education, Attending Physician, Mount Sinai Hospital Medical Center, Chicago, Illinois
Contributor Information and Disclosures

Updated: Mar 6, 2008

Introduction

Background

Hippocrates described an array of facial injuries as long ago as 400 BCE. In 1823, von Graeffe described the use of an elastic tube placed in the nares to maintain an open airway. During the early 20th century, Sir Harold Gilles, father of plastic surgery, taught army personnel about breathing problems in patients with facial injuries. He recommended positioning them supine to maintain an airway. Frenchman René Le Fort studied cadavers in 1901 and described 3 basic types of facial fractures. Endotracheal anesthesia and radiography, developed during the First World War, led to a better understanding and treatment of facial fractures. During the Second World War, a multidisciplinary approach to treatment of facial fractures continued to improve outcomes of severely injured soldiers. Advent of CT-guided reconstruction, along with new surgical techniques, has improved the final appearance of patients with bony injuries immensely.

Pathophysiology

Maxillofacial fractures are the result of blunt or penetrating trauma. Most are blunt injuries caused by vehicular crashes, altercations, sporting-related trauma, occupational injuries, and falls. Penetrating injuries are mainly the result of gunshot wounds, stabbings, and explosions.

Determinants of type of injury (ie, soft tissue alone vs bony) are shape and velocity of the striking object.

The amount of force needed to fracture different bones of the face has been studied, and these bones have been divided into those that require high impact to fracture (greater than 50 times the force of gravity [g]) and those that require only low impact to fracture (less than 50 g).

• High impact
  • Supraorbital rim - 200 g
  • Symphysis of the mandible - 100 g
  • Frontal-glabella - 100 g
  • Angle of mandible - 70 g
• Low impact
  • Zygoma - 50 g
  • Nasal bone - 30 g

Mandibular fractures usually occur in 2 or more locations because of the bone's U shape and articulations at the temporomandibular joints. Fractures also may occur at a site apart from the site of direct trauma. A large percentage of mandibular fractures are open, as they often fracture between teeth and communicate with the oral cavity.

Different mechanisms are associated with varying locations. Fractures from automobile crashes most frequently occur at the condyle and symphysis, those from motorcycle accidents at the symphysis and alveolus, and those from altercations mostly at the condyles, angles, and body.

For more information, see Medscape's Trauma Resource Center.

Frequency

United States

The mandible is the third most fractured bone of the face. Of these fractures, approximately 20-35% are at the condyle and ramus, 20-30% at the angle, 15-30% at the body, 8-20% at the symphysis, and 1-5% at the alveolar ridge.

One study placed the incidence of severe maxillofacial injury (fractures, lacerations) at 0.04-0.09% for motor vehicle crashes. Incidence of fractures due to motor vehicle injuries is higher in rural areas; altercation-related injuries are more frequent in inner cities.

Mortality/Morbidity

• Incidence of other major injuries is as high as 50% in high-impact mandibular fractures, whereas it is 21% in low-impact fractures. Mortality rate in high-impact fractures is as high as 12%, yet death rarely results directly from maxillofacial injury.
• Patients who are involved in motor vehicle crashes are more likely to have additional injuries than patients with violence-related injuries.
• Incidence of associated cervical spine injuries ranges from 0.2-6%.

Sex

Adult male-to-female ratio is 3:1. Suspect domestic violence or sexual assault in women as this may coexist in 30% of cases.

Age

Male predominance is reduced to 3:2 in children. In nonmotor vehicle injury, the possibility of child abuse should be a concern.

Clinical

History

• Since maxillofacial fractures are the result of trauma, primary survey and attention to airway, breathing, and circulation takes priority.
• Focus primary evaluation on patency of airway, control of cervical spine, breathing and circulatory impairment, and loss of consciousness if patient is experiencing neurologic impairment.
• Once life threats are addressed, obtain a thorough history.
  • Allergies
  • Medications
  • Medical history
  • Last meal
  • Events leading to injury
• Next, ask specific questions regarding the facial injury.
  • Does patient have epistaxis or clear fluid running from nares or ears?
  • Did patient lose consciousness? If so, for how long?
  • Has patient had any visual problems, such as double or blurred vision?
  • Has patient had any hearing problems, such as decreased hearing or tinnitus?
  • Does patient have any malocclusion, and is patient able to bite down without pain?
  • Does moving the jaw cause pain or spasm?
  • When the jaw moves, is a grinding sound produced?
  • Does the patient have areas of numbness or tingling on the face?
  • In women, ask if the injury was from a partner or if they feel threatened by anyone.
  • In children, ask questions to determine if child abuse is an issue.

Physical

• Complete exam of the face is necessary, since multiple injuries can occur easily. Portions of the exam specific to the mandible are marked with an asterisk (*).
  • Inspect face for asymmetry, performed while looking down from head of bed.
  • Inspect open wounds for foreign bodies and palpate for bony injury.
  • Palpate bony structures of supraorbital ridge and frontal bone for step-off fracture.
  • Thoroughly examine eyes for injury, abnormal ocular movements, and visual acuity.
  • Inspect nares for telecanthus and widening of nasal bridge, then palpate for tenderness and crepitus.
  • Inspect nasal septum for septal hematoma and clear rhinorrhea, which may suggest cerebrospinal fluid (CSF) leak.
  • Palpate zygoma along its arch as well as along its articulations with the frontal bone, temporal bone, and maxillae.
  • Check facial stability by grasping teeth and hard palate and gently pushing back and forth then up and down, feeling for movement or instability of midface.
  • *Test teeth for stability and inspect for bleeding at gumline, a sign of fracture through the alveolar bone.
  • *Check teeth for malocclusion and step-off.
  • *Palpate mandible for tenderness, swelling, and step-off along its symphysis, body, angle, and coronoid process anterior to the ear canal.
  • *Check for localized edema or ecchymosis in the floor of the mouth.
  • Evaluate distributions of the supraorbital, infraorbital, *inferior alveolar, and *mental nerves for anesthesia.
  • *If teeth are missing, account for them to ensure they have not been aspirated.
  • *Inspect area just anterior to the meatus of the ear for ecchymosis and palpate for tenderness. This is the condyle of the mandible and site of an often-missed fracture. Plain radiographs are not good at visualizing the condyle, thus maintain a high level of suspicion if physical exam is suggestive.
  • *Mandibular fracture is suggested by inability to open mouth, trismus, malocclusion of teeth, or palpable step-offs of bone along symphysis, angles, or body. Gingival bleeding at the base of a tooth suggests fracture, especially if teeth are malaligned. Edema or ecchymosis may be present in the floor of the mouth. Neurologic findings may include hypesthesia in distribution of inferior alveolar or mental nerves.

Causes

• Motor vehicle accidents, as occupant or as pedestrian stuck by the vehicle
• Violence, by being struck with fists, feet, or objects including bullets in penetrating injuries
• In falls, either from a height or in cases of syncope 

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