Cervical Branch of the Facial Nerve: Platysma Innervation
- Nerve
- Highlighted area
Quick facts
- Definition
- Terminal branch of the facial nerve that descends into the neck and provides motor innervation to the platysma muscle.
- Origin
- Arises from the parotid plexus of the facial nerve, in the region of the parotid gland.
- Function
- Contraction of the platysma, which tightens the neck skin and pulls the lower corner of the mouth downward.
- Relevance in orofacial harmonization (HOF)
- Safety landmark when treating platysmal bands, double chin and the transition between jaw and neck.
The cervical branch of the facial nerve is one of the terminal branches of that nerve and carries the motor signal to the platysma, the thin, wide muscle that covers the front of the neck. It arises in the plexus that forms inside the parotid gland, emerges near the angle of the jaw and descends toward the neck.
What is its course?
After leaving the parotid, the cervical branch passes just below the angle of the jaw and continues beneath the platysma, on the deep surface of the muscle. Along the way, it may communicate with the marginal mandibular branch and with branches of the cervical plexus, which supply sensation to the neck skin.
| Facial nerve branch | Muscles supplied | Region |
|---|---|---|
| Temporal | Frontalis, part of the orbicularis | Forehead and temple |
| Zygomatic | Orbicularis oculi | Eye region and cheekbone |
| Buccal | Buccinator, upper lip muscles | Cheek and upper lip |
| Marginal mandibular | Lip depressors and mentalis | Jaw and chin |
| Cervical | Platysma | Neck |
The cervical branch is the lowest of the series. Like the others, it can vary in course and connections between individuals, so no description is an exact map.
What does the platysma do?
The platysma is a superficial muscle, attached to the skin and to the SMAS. When it contracts, it tightens the neck skin and pulls the corner of the mouth and the lower lip downward. With age, it can form vertical bands that are visible on effort, the so-called platysmal bands, and contribute to the look of a double chin and of horizontal neck lines.
The relationship between the cervical branch and the platysma explains why treating platysmal bands, when indicated, calls for care: the effect on the muscle can change the neck's tension function and the position of the corner of the mouth, and the technique must respect the anatomy.
Why does this matter in orofacial harmonization (HOF)?
Procedures on the jawline, double chin and neck pass through a region with variable nerve, vascular and glandular structures. Knowing the course of the cervical branch and the marginal branch helps explain why motor complications, although rare, exist and why planning requires individual assessment.
This topic is related to subplatysmal fat, which sits beneath the muscle and influences the contour of the neck.
Also called: cervical branch of the facial nerve, cervicofacial branch (lower).
Frequently asked questions
What happens if the cervical branch is injured?
The platysma on the affected side may weaken, with asymmetry when pulling the corner of the mouth downward. It is usually less obvious than injury to other branches of the facial nerve, but it should be investigated.