Facial plane is formed by
**Core Concept**
The facial plane is a fascial layer that separates the superficial and deep layers of the cervical fascia. It plays a crucial role in facial expressions and is composed of a thin fibrous layer that is continuous with the superficial cervical fascia.
**Why the Correct Answer is Right**
The facial plane is formed by the orbicularis oculi, zygomaticus major, and other muscles of facial expression that insert into it. This plane is also connected to the superficial cervical fascia, which is a layer of loose connective tissue that covers the neck muscles. The facial plane is essential for transmitting the forces of facial expressions to the deeper structures of the face.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because the platysma muscle is a superficial muscle that lies superficial to the facial plane, not forming it.
**Option B:** Incorrect because the investing layer of the deep cervical fascia is a deeper layer that encloses the neck muscles, not forming the facial plane.
**Option C:** Incorrect because the deep fascia of the face is a deeper layer that lies beneath the facial plane, not forming it.
**Clinical Pearl / High-Yield Fact**
The facial plane is an essential landmark for surgeons and anatomists, as it separates the superficial and deep layers of the face and is crucial for understanding facial expressions and the transmission of forces through the face.
**Correct Answer: C. The facial plane is formed by the orbicularis oculi, zygomaticus major, and other muscles of facial expression.**