Zygomatic Branch of the Facial Nerve: Anatomy
- Nerve
Quick facts
- Origin
- Branches of the facial nerve that leave the anterior and upper border of the parotid gland.
- Course
- They run forward and upward, over the body of the zygomatic bone, toward the outer corner of the eye.
- Muscles
- Lower part of the orbicularis oculi, zygomaticus major and minor, and levator labii superioris.
- Function
- Full eye closure and elevation of the corner of the mouth and the lip in the smile.
- Relevance in orofacial harmonization (HOF)
- Passes through the cheekbone region and the zygomatic ligament, where fillers and threads are placed.
The zygomatic branch of the facial nerve is the set of branches that leaves the anterior and upper border of the parotid gland and runs forward and upward, over the zygomatic bone, to the outer corner of the eye and the smile muscles. It controls the lower part of the orbicularis oculi, the zygomaticus major and zygomaticus minor muscles, and the levator labii superioris. It is one of the five branches of the facial nerve.
What is the course of the zygomatic branch?
| Segment | What to look for |
|---|---|
| Exit | Anterior and upper border of the parotid, usually as more than one branch |
| Arch and body of the zygomatic | Runs beneath the SMAS, crossing the cheekbone region |
| Zygomatic ligament | Branches pass near the area of the zygomatic ligament, a firm anchoring point of the cheek |
| Reaching the muscles | Enters the zygomaticus major and minor through their deep surface and reaches the orbicularis oculi from below |
The upper branches communicate with the temporal branch, and the lower ones with the buccal branch. This network provides some redundancy: partial injuries tend to recover better than in the temporal or marginal mandibular branch, but the pattern varies between people.
Why does the zygomatic branch matter in orofacial harmonization (HOF)?
- Eye closure: the lower part of the orbicularis oculi depends on it. Weakness shows up as difficulty closing the eye forcefully.
- Smile: the zygomaticus muscles raise the corner of the mouth. Weakness or toxin diffusion to these muscles changes the height of the smile on one side. See asymmetric smile after toxin.
- Cheekbone and zygomatic area: cheekbone filler and zygomatic filler are done in the region the nerve crosses. The plane of the product is an anatomical decision by the professional.
- Midface threads: threads that cross the cheek pass through the branch's territory, which calls for knowledge of the layers.
How does it show up in the assessment?
- Function test: ask the person to close the eyes tightly and smile showing the teeth, comparing the sides.
- History: Bell's palsy, facial or parotid surgery, previous threads and toxin injections around the eyes.
- Video documentation: a spontaneous smile shows asymmetries that a posed photo hides.
Also called: zygomatic branches of the facial nerve, ramus zygomaticus. Not to be confused with the zygomatic nerve, which is sensory and comes from the trigeminal nerve.
Frequently asked questions
What is the function of the zygomatic branch of the facial nerve?
It controls the lower part of the orbicularis oculi, which helps close the eye forcefully, and the zygomaticus and lip levator muscles, which raise the corner of the mouth and the upper lip in the smile.
Can cheekbone filler reach the zygomatic branch?
Nerve injury from filler is uncommon, because the branches run beneath the SMAS and the product usually stays in other planes. Knowing the course is part of safety, especially with threads and cannulas that cross the region.