Early stabilization is important to maximize both cosmetic integrity and anatomical functionality 1. In fact, the zygotic arch is one of the most commonly fractured facial bones, typically following altercations in which the patient is punched in the face.
Radiographic confirmation of zygotic arch fractures allows early stabilization with better anatomic function and cosmetic results. It borders the frontal bone lateral to the orbit and the sphenoid and maxilla medially.
The zygotic bone has four projections, which give it the characteristic quadrilateral (diamond) shape. The zygotic bone is responsible for the Malay prominence, an important aesthetic landmark in facial architecture.
The zygotic arch provides width to a person’s face and figures prominently in the oblique facial profile. Besides its aesthetic significance, the zygotic -maxillary region plays an important functional role.
The Malay surface is convex and is perforated by a small central aperture called the zygomaticofacial foramen. A slight elevation just inferior to this foramen is the site of origin of the zygomaticus muscle.
The temporal surface is concave with a rough triangular area medially for articulation with the maxilla and a smooth concave surface laterally that forms the anterior boundary of the temporal fossa and the lower part of the infra temporal fossa. A small protuberance called the orbital tubercle is the site of attachment of the lateral algebra ligament.
There are a pair of zygomaticotemporal foramens present on the medial deep surface of the bone. The anterosuperior or maxillary border is rough and beveled at its inner table to articulate with the maxilla.
The site of origin of the quadrats labia superiors muscle is near the orbital margin. The posteroinferior or zygotic border provides attachment on its rough edge to the masseter muscle.
The skull bones of an infant are more resilient compared to an adult because they are separated by fibrous cultural ligaments. The type of skull bone fracture largely depends on the location and intensity of the trauma as well as the age of the patient.
The adult skull can be compared to an eggshell with limited strength and resilience beyond which it breaks. In a young child, the skull can be compared to a table tennis ball where a blow creates a depression without causing a break in the bone.
Falls, fist fights, and motor vehicle accidents are the most common causes of facial fractures. Signs of fracture of the facial bones include deformity, ocular/orbital displacement, abnormal movements accompanied by cracking or rattling sounds, and malocclusion of the teeth.
This type of trauma can result in an isolated fracture, such as from the impact of a clenched fist. However, it can also occur in conjunction with other fractures of the face, usually as a result of MVA's or other high-impact injuries.
Moderate force can cause slightly displaced or non-displaced fractures at the suture lines. More forceful trauma usually results in displacement of the zygote inferior, medially, or posteriorly.
Bottom: Areas of the Zygotic Bone that are Commonly Fractured (© Osborne Head & Neck Institute). This type of comminuted fracture that results in separation at the suture lines usually occurs during high-impact motor vehicle accidents or explosions.
Patients with suspected facial trauma and/or zygotic fractures are evaluated primarily with craniofacial X -rays or CT scans. Occipitomental (OM) or Water’s View: This is an angled PA radiograph of the skull taken with the patient erect and facing an upright IR.
Submentovertex (MV) View: This is a radiograph taken with the patient’s chin raised and neck fully extended. Cervical spine injuries and fractures must be ruled out prior to attempting this projection in trauma patients.
With advancements in medical technology, high-resolution computerized tomography (CT) scans have, for the most part, become the imaging modality of choice in patients with facial trauma. Compared to plain film radiography, CT scans more clearly demonstrate the complex bony anatomy of the face and the intricacy of injuries resulting from facial trauma.
Mildly displaced comminuted fracture of the left zygotic arch shows up to 37 degrees of inwards angulation. The zygotic arch is the third most common fractured facial bone, with a high majority of those cases being male.
Early stabilization is important to maximize both cosmetic integrity and anatomical functionality 1. NICE has issued rapid update guidelines in relation to many of these.
The upper and lower walls of the cavity are described as the roof and the floor. The orbital margin (rim) is strong and, superiorly, it contains the supra orbital notch/foramen which transmits vessels and nerves.
The zygote forms part of the floor and lateral wall of the orbit and the zygotic arch is an important feature in the structure and appearance of the face. This plays a key role in the structure and function of the facial skeleton.
Maxillofacial fractures can have various causes, including traffic accidents, falls, assaults and sports injuries. The incidence and causes of maxillofacial trauma and facial fractures vary widely in different regions of the world due to social, economical and cultural consequences, awareness of traffic regulations and alcohol consumption.
A CT scan facial series is often essential to planning surgery. CT may also show intracranial injury which may be present in about half of patients.
Displaced Malay complex fractures may increase orbital volume due to angulation of the zygomaticosphenoid suture or orbital floor blowout. Ultrasound is sometimes used for visualization of the zygotic arch and anterior wall of the frontal sinus, particularly following reduction to avoid further radiation exposure.
CT scanning is currently the gold standard in the imaging of orbital fractures, but MRI may be a useful alternative. This usually follows a blow from an object >5 cm (e.g., a tennis ball).
Vertical diplopia (double vision, especially on looking up) with restriction of up gaze. It is worth noting that children may have a 'green stick' fracture with significant muscle entrapment but minimal bruising (a 'white-eye blowout').
Liaise with ophthalmologists and maxillofacial surgeons (depending on local protocol). Some cases are managed conservatively with prophylactic broad-spectrum antibiotics (e.g., co-amoxiclav) and outpatient monitoring.
There is symptomatic enophthalmos of >2 mm (this can easily be measured in the eye clinic). These are rare in isolation but may accompany orbital floor fractures.
They are characterized by subcutaneous emphysema, variable ecchymosis and medial rectus dysfunction (difficulty in rotating the eye towards the nose, associated with diplopia). Surgical repair is considered if there is significant pain or diplopia secondary to muscle entrapment.
Hematoma of the upper lid and particular ecchymosis which may spread to the other side over a few hours. Look for a superior subconjunctival hemorrhage with no distinct posterior limit.
Although small fractures may be managed conservatively, the patient needs to be monitored closely for possible cerebrospinal fluid (CSF) leak. Lateral wall fractures are therefore more commonly seen following significant maxillofacial trauma involving the Malay complex too.
Posterior displacement of the fractured fragment may impair movement of the mandible, causing difficulty with chewing. Look for decreased range of mouth opening (normal should be >30 mm).
Where a patient has multiple injuries or is severely unwell, surgery is often delayed. The precise approach will depend upon the injuries seen on the CT film and open surgical reconstruction may also have to be undertaken.
A multidisciplinary approach may be required in complex cases, using expertise from plastic surgery, facio-maxillary surgery, ear, nose and throat (ENT) and neurosurgery, depending upon other associated injuries. Antibiotics are normally prescribed with complex fractures and a short course of steroids may be used to reduce inflammation.
Careful follow-up is required to ascertain that there is good functional recovery, including the ability to eat and chew, eye position and normal facial anatomy. Failure to treat, risks cosmetic deformity or limited mandibular movement.
Seat belts are important in reducing injuries in road traffic accidents. A Brazilian study looking at the relationship between facial injuries and seat belt wearing suggested that: The driver position shows the highest incidence of facial fractures and was not effectively protected against this by the use of a seat belt.
The wearing of seat belts seems to protect against facial fractures in front-seat passengers. There was a high incidence of facial fractures among rear-seat passengers, but it was not possible to evaluate the effect of seat belt use in this group.
Alcohol and binge-drinking are major contributory factors to assaults and facial injury. Many argue for harm-reduction measures such as the use, in licensed premises, of glasses and bottles made of plastic, controlling drink prices and targeted policing.
Other measures include the introduction of minimum price per unit and modifying marketing and availability. Appropriate protective equipment may reduce sports-related injuries, but the evidence is of poor quality.
Adam AA, Hi L, Bing LA, et al. ; Evaluation of treatment of zygotic bone and zygotic arch fractures: a retrospective study of 10 years. Hwang K, You SH ; Analysis of facial bone fractures: An 11-year study of 2,094 patients.
Challah PO, Ekanaykaee K, Bare CJ, et al. ; Diagnosis and management of common maxillofacial injuries in the emergency department. Part 3: Orbitozygomatic complex and zygotic arch fractures.
Hopper RA, Salem S, She RAW ; Diagnosis of midface fractures with CT: what the surgeon needs to know. Folk A, Swimmer H, Loafer M, et al. ; High resolution magnetic resonance imaging with an orbital coil as an alternative to computed tomography scan as the primary imaging modality of pediatric orbital fractures.