The facial nerve splits into five main branches that control the muscles of facial expression. These branches are:
The Five Branches of the Facial Nerve
The facial nerve, also known as cranial nerve VII, is responsible for controlling the muscles of the face, allowing us to smile, frown, and make various other expressions. This important nerve divides into five major branches. Here’s a detailed look at each one:
| Branch | Area Innervated | Function |
|---|---|---|
| Frontal (Temporal) | Muscles of the forehead and scalp | Elevates the eyebrows and wrinkles the forehead (e.g., when surprised) |
| Zygomatic | Muscles around the eyes and upper cheeks | Controls muscles for smiling, eye closure, and lifting the upper lip |
| Buccal | Muscles of the cheeks, upper lip, and nose | Controls muscles for smiling, lip movement, and facial expressions around the mouth |
| Marginal Mandibular | Muscles of the lower lip and chin | Controls muscles for lower lip movement, frowning, and expression of sadness |
| Cervical | Platysma muscle in the neck | Controls neck muscles involved in expressions and movement of the skin on the neck and around the mouth |
Details on Each Branch
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Frontal (or Temporal) Branch: This branch controls the muscles that allow us to raise our eyebrows and wrinkle our foreheads, which contributes to expressions like surprise or concern.
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Zygomatic Branch: Responsible for the movement of muscles surrounding the eyes and upper cheeks, this branch allows us to smile, close our eyes tightly, and lift our upper lip.
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Buccal Branch: This branch controls muscles in the cheeks, upper lip, and around the nose. It plays a significant role in expressions around the mouth, like smiling, and also helps with actions like blowing air.
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Marginal Mandibular Branch: Located in the lower face, this branch controls the muscles that move the lower lip and chin. It allows us to express sadness, frown, and control the shape of our mouth.
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Cervical Branch: The cervical branch of the facial nerve controls the platysma muscle in the neck which influences the skin movement of the lower face and neck.
Importance of these Branches
Understanding the specific function of each branch is crucial in the diagnosis and treatment of facial nerve injuries. Damage to a particular branch can result in paralysis or weakness of the specific facial muscles it innervates, leading to facial asymmetry or difficulty with certain expressions. According to the provided reference, the facial nerve breaks into these 5 specific branches: "frontal (or temporal), zygomatic, buccal, marginal mandibular, and cervical" .
