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Zygomatic Arch Dislocation

What is Zygomatic Arch Dislocation?

The zygomatic arch is the bony “cheekbone” that forms the lateral border of the orbit and gives the face its contour. A zygomatic arch dislocation occurs when this bone segment is displaced from its normal articulation with the temporal bone or the maxilla, usually after a significant blunt force to the face. Unlike a fracture, which breaks the bone, a dislocation shifts the whole arch without necessarily breaking it. The condition can cause noticeable facial asymmetry, pain, difficulty opening the mouth, and may impair the function of the temporomandibular joint (TMJ).

Because the facial skeleton is tightly interconnected, a dislocated arch often signals other injuries to the orbit, mid‑face, or skull base. Prompt assessment is essential to avoid long‑term deformity, nerve injury, or vision problems.

Common Causes

• Motor‑vehicle collisions – especially side‑impact or “T-bone” crashes that strike the cheek.
• Sports injuries – contact sports (football, rugby, martial arts) or a punch to the face.
• Falls – slipping and landing directly on the side of the face.
• Physical assault – a blow from a fist, bat, or other hard object.
• Industrial accidents – being struck by a moving piece of equipment or heavy debris.
• High‑energy projectile injuries – such as shrapnel or gunshot wounds that impact the cheek region.
• Severe facial burns – contracture of the soft tissues can indirectly displace the arch.
• Congenital or developmental abnormalities that weaken the zygomatic suture, making it more susceptible to displacement after minor trauma.
• Repetitive micro‑trauma – e.g., chronic boxing or certain occupational exposures that gradually loosen the arch.
• Pathological bone loss – conditions such as osteomyelitis or metastatic disease that erode bone integrity.

Associated Symptoms

Patients with a zygomatic arch dislocation often notice more than just a “bump” on the cheek. Common accompanying signs include:

• Sharp, throbbing pain at the lateral cheek, worsened by chewing or jaw movement.
• Visible facial asymmetry – the affected side may appear sunken or protruded.
• Swelling or hematoma that spreads to the orbit or upper jaw.
• Limited mouth opening (trismus) due to tension on the muscles of mastication.
• Clicking, grinding, or locking of the TMJ.
• Numbness or tingling in the cheek, upper lip, or lower eyelid (injury to the infra‑orbital nerve).
• Double vision or difficulty moving the eye if the orbital floor is involved.
• Headache, especially around the temple or behind the ear.

When to See a Doctor

Facial trauma should always be evaluated by a healthcare professional, but the following situations warrant **immediate** medical attention:

• Severe, worsening pain that is not relieved by over‑the‑counter analgesics.
• Visible deformity or a “step” in the bone contour.
• Bleeding that does not stop after 10–15 minutes of gentle pressure.
• Swelling that spreads rapidly or causes difficulty breathing.
• Changes in vision, double vision, or eye pain.
• Persistent numbness or loss of sensation in the face.
• Inability to open the mouth more than a few centimeters.
• Signs of concussion or head injury (loss of consciousness, vomiting, confusion).

Diagnosis

Accurate diagnosis combines a thorough clinical exam with imaging studies.

Clinical Evaluation

• History taking – mechanism of injury, time since trauma, prior facial surgeries.
• Inspection – note swelling, bruising, asymmetry, skin lacerations.
• Palpation – gently feel the zygomatic arch; a “step-off” or crepitus suggests displacement.
• Functional testing – assess jaw movement, bite force, and nerve sensation.

Imaging Studies

• Plain radiographs (X‑ray) – limited utility; may miss subtle dislocations.
• CT scan (computed tomography) – the gold standard; provides detailed 3‑D view of bone alignment, associated fractures, and orbital involvement.
• Cone‑beam CT – lower radiation dose, useful for dental and maxillofacial specialists.
• MRI – reserved for evaluating soft‑tissue injury, nerve damage, or when a concurrent TMJ disorder is suspected.

Specialist Consultation

Depending on severity, patients may be referred to an oral‑and‑maxillofacial surgeon, otolaryngologist, or plastic surgeon with facial trauma expertise.

Treatment Options

Management aims to restore normal anatomy, relieve pain, and prevent long‑term complications.

Non‑Surgical (Conservative) Management

• Rest and ice – 20 minutes on, 20 minutes off for the first 24–48 hours.
• Analgesics – acetaminophen or NSAIDs (ibuprofen) as tolerated.
• Soft diet – avoid hard or chewy foods for 1–2 weeks.
• Physical therapy – gentle jaw‑opening exercises after pain subsides.
• Close monitoring – repeat imaging in 1–2 weeks if symptoms persist, to ensure the arch remains reduced.

Conservative care is appropriate only when imaging confirms that the arch is properly aligned or minimally displaced and there is no associated fracture.

Surgical Intervention

Most dislocations, especially those with significant displacement or concurrent fractures, require reduction.

1. Closed reduction – performed under sedation or general anesthesia; a surgeon applies external pressure to reposition the arch without an incision.
2. Open reduction and internal fixation (ORIF) – indicated for:
   • Failure of closed reduction.
   • Comminuted fractures of the arch.
   • Associated orbital floor or maxillary fractures.
   Small titanium plates or absorbable screws are used to hold the bone in place.
3. Post‑operative care – similar to conservative measures plus wound care, antibiotics (usually a single dose of a first‑generation cephalosporin), and instructions to avoid pressure on the cheek for 4–6 weeks.

Rehabilitation

• Gradual return to normal diet.
• Jaw‑stretching exercises to prevent trismus.
• Regular follow‑up visits for clinical exam and repeat imaging.

Prevention Tips

While not all facial injuries can be avoided, the risk of a zygomatic arch dislocation can be reduced with the following measures:

• Wear protective facial gear – helmets with face shields for cycling, motorcycling, skateboarding, and contact sports.
• Use mouthguards – especially in boxing, mixed martial arts, and rugby.
• Maintain safe environments – secure loose rugs, adequate lighting, and handrails to prevent falls.
• Follow traffic safety rules – seatbelt use, obey speed limits, and avoid distracted driving.
• Strengthen neck and facial muscles – regular conditioning may lessen the force transmitted to the cheek during impact.
• Promptly treat dental or sinus infections – chronic infection can weaken bone.
• Seek early evaluation for any facial trauma, even if it seems minor.

Emergency Warning Signs

Key Takeaways

• A zygomatic arch dislocation is a displacement of the cheekbone, usually from a high‑energy impact.
• It can cause pain, swelling, facial asymmetry, trismus, and nerve numbness.
• CT imaging is the diagnostic gold standard; early detection prevents chronic deformity.
• Mild cases may be managed conservatively, but most require reduction—often surgical.
• Prompt medical evaluation is crucial, especially if vision changes, severe pain, or neurological signs develop.
• Protective equipment and safe practices are the best ways to lower the risk.

For further reading, consult reputable sources such as the Mayo Clinic, CDC, NIH, and the Cleveland Clinic.

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