Fracture Zygoma and its Management
Zygomatic bone occupies a prominent position in the facial skeleton. It forms a significant portion of the lateral wall and floor of the orbit. It also plays an important role in the formation of malar eminence, thus determines the facial morphology. Fractures involving the zygomatic bone involves disarticulation of the zygoma at the zygomatico frontal suture, zygomatico maxillary suture, and along the zygomatic arch. If fracture zygoma involves these three sutures it is known as "tripod fracture".
Zygomatic bone also articulates with the sphenoid bone which could be involved in these fractures
Zygoma is a quadrilateral bone. The body of the zygoma forms the malar prominences. A prominent malar prominence is considered to be a sign of youth and beauty. It has four projections which help in its articulation with the surrounding facial bones. These projections are:
1. Superior: The zygoma articulates with the frontal bone at the fronto zygomatic suture line
2. Articulation with the maxilla: This articulation is wider involving both the anterior and lateral walls of the antrum
3. Cruved bony projection that forms the lateral orbital wall and the lateral aspect of infra orbital rim and floor
4. Laterally it extends as zygomatic arch to attach to the temporal bone at the zygomatico temporal suture line
5. Posteriorly the zygoma articulates with the sphenoid bone
The zygomatic bone acts as an important buttress between the maxilla and skull. Its prominent location makes it prone to fracture during injuries to facial skeleton. The mechanism of injury usually involves a blow to the side of the face. Depending on the severity of injury, the fracture could be a simple depressed one or severely displaced and comminuted one. Comminuted fractures are commonly caused by high velocity injuries sustained during road traffic accidents.
1. Swelling over malar region
2. Tenderness and crepitus
3. Vision disturbances due to muscle entrapment, neuromuscular injuries or intramuscular hematoma
5. Epistaxis due to laceration of maxillary sinus mucosa
6. Periorbital / subconjuntival ecchymosis
7. Paresthesia in the distribution of infraorbital, zygomatico facial or zygomatico temporal nerves
8. Posterior displacement of fractured fragment may cause mandibular movement disturbances causing difficulty in chewing food
Ruler test to identify fracture zygoma:
Two rulers are used as shown in the figure to perform this test. These rulers are placed in front of the ears. Ruler is found to deviate on the side of fracture.
Figure showing Ruler test being performed
X-ray paranasal sinuses water's view will demonstrate fracture of zygoma.
X-ray paranasal sinuses showing fracture of arch of zygoma
CT scan both axial and coronal sections of paranasal sinuses is diagnostic.
Axial CT PNS showing fracture of anterior wall of maxilla and zygoma
Non displaced / minimally displaced fractures of zygoma donot require surgical intervention. Displaced / comminuted fractures require open reduction and internal fixation.
When fractures involving zygomatico maxillary complex is not comminuted, it can be managed by reducing the whole zygoma as a single unit. Reduction can be performed through upper gingivobuccal incision.
Gillie's technique of reducing fracture zygoma:
Small incision is made over temporal area superficial temporal artery is avoided
Auricularis superior muscle is cut along the line of its muscle fibers
Temporalis fascia is cut with a knife
Periosteal elevator is inserted through the incision and the fractured fragment is elevated. A gauze piece is used as a leverage
Figure showing fracture arch of zygoma being reduced.
Orbital exploration is indicated in the following circumstances:
1. Severe comminution
2. Displacement of orbital rim
3. Displacement of greater than 50% of the orbital floor with prolapse of orbital contents into the maxillary sinus
4. Orbital floor fracture of greater than 2 cm2
5. Combination of inferior and medial orbital wall fractures
6. Suspected involvement of orbital apex