In short. The nerve nearest the operative field, what it controls, how the approach keeps it out of harm, and what a weakness would look like afterwards.
Key points
- The useful question is not whether the nerve can be injured, because that is a risk of any operation in this region.
- It is how the approach keeps it out of the way, what the plane of dissection will be, and what a weakness would mean for you if it happened.
- A surgeon who can describe the plane is planning around a structure rather than around an amount of bone.
The zygomatic branch of the facial nerve is the structure this operation is planned around. It crosses the region through which the cheekbone is reached, and the decisions about approach and plane of dissection are made so that it stays outside the operative field rather than being met inside it.
What it is and where it runs
It is one branch of the facial nerve, which leaves the skull behind the ear and divides into branches supplying the muscles of expression. The zygomatic branch travels forward and upward across the side of the face, passing through the tissue over the cheekbone on its way to the muscles around the eye and the upper cheek. It is not visible from the surface, and its exact position varies between individuals.
What it controls
The muscles that close the eye and the muscles that lift the corner of the mouth. A weakness therefore shows in two places. Around the eye, the lid may close less firmly, which can mean watering or a sense of dryness. Around the mouth, the smile on that side may lift less, which is the change patients notice first because it appears in every photograph.
Ask where the nerve runs in your case
The useful question is not whether the nerve can be injured, because that is a risk of any operation in this region. It is how the approach keeps it out of the way, what the plane of dissection will be, and what a weakness would mean for you if it happened. A surgeon who can describe the plane is planning around a structure rather than around an amount of bone.
How the approach keeps it out of the field
By choosing where the tissue is entered and in which layer the dissection travels. Different approaches to the cheekbone place the working plane in different relationships to the nerve, and the choice follows from which structure is being moved and from the anatomy of that face. The nerve stays in tissue that is not being worked in, and the operation proceeds on bone beneath a plane that has already been established.
How a weakness is followed up
By being looked for rather than waited out. If the two sides of the face move differently in the days after surgery, that is recorded and followed at intervals, because the direction of travel matters more than the finding itself. Weakness that is improving is watched; weakness that is worsening, or that comes with difficulty closing the eye, is assessed urgently.
What to establish before agreeing to surgery
- Which approach will be used, and what plane of dissection it places the operation in.
- What a weakness around the eye or the smile would mean for you in the weeks afterwards.
- How a difference between the two sides would be followed up, and by whom.
The nerve does not make this operation unreasonable. It makes it an operation with a specific risk that is managed by planning rather than discovered afterwards.
Frequently asked questions
What does the zygomatic branch of the facial nerve control?
The muscles around the eye and across the upper cheek. In practical terms it contributes to closing the eye firmly and to the movement that lifts the corner of the mouth into a smile. It is one branch of the facial nerve, and it crosses the region through which the cheekbone is reached, which is why the approach is planned around it.
Would I notice if it were affected?
Usually as a difference between the two sides rather than as a loss of function. The eye on that side may close less firmly or feel as though it waters more, and the smile may lift less on one side. Most weakness after this kind of surgery is temporary and improves over weeks to months as the nerve recovers, and a lasting weakness is uncommon but possible.
Can the nerve be seen on a scan?
Not directly on the imaging used to plan the bone. Its course is inferred from surface landmarks, from the anatomy of the region and from the surgeon's knowledge of where it usually runs. That is why the approach and the plane of dissection matter more than any picture: they place the operative field away from where the nerve is expected to be.
Risks & Limitations
- The change to the bone is permanent. Bone that has been cut away cannot be restored as it was, so the amount removed is decided from imaging and treated as fixed once it has been set.
- The cheekbone is a support. Removing part of it removes part of what holds the midface up, so hollowing in the temple or the cheek is a property of the operation rather than a complication of it, and it is discussed before surgery rather than after it.
- The zygomatic branch of the facial nerve crosses the region the operation works in. Weakness around the eye or the smile after surgery is usually temporary and usually resolves over weeks to months; a lasting weakness is uncommon but possible.
- Swelling hides the width for months. The face reads unevenly at two to three weeks, is not close to final until four to six months, and is judged honestly between six and twelve months.
- Numbness of the cheek and the upper lip is expected after this operation, is watched rather than treated in the early weeks, and may not return fully in some areas.
- The two sides of a face are rarely identical, and reducing both by the same amount can make a difference that was always present more visible rather than less.
- The operation changes the width at the level of the eyes and the outline behind the cheek. It does not narrow the lower face, change the bite, lift the soft tissue, or alter the skin.
When to Seek Care
- Swelling that is increasing rather than settling after the first week, or that is much greater on one side — contact the team.
- A wound that is opening, or discharge, spreading redness or warmth around an incision.
- A weakness around the eye or the smile that is worsening rather than improving, or an eye that will not close — seek emergency care at once.
- Fever, or feeling generally very unwell with a wound or a swollen area.
- Calf pain, swelling or tenderness in one leg, or shortness of breath or chest pain — seek emergency care at once.
References & Further Reading
- American Society of Plastic Surgeons (ASPS) — procedure and safety guidance
- National Institute for Health and Care Excellence (NICE, UK) — relevant guidance
- Cochrane Library — systematic reviews
- Chinese Medical Association Plastic Surgery Branch — clinical guidance
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.