Maximum Safety

Facial Nerves

What to protect at all costs. Nerve injury is the most feared complication in facial surgery.

"You cannot protect what you don't know. And you cannot know what you don't see."

— Direct Vision Principle

Facial Nerve (VII) — Motor Branches

Facial movement — injury causes paralysis

Temporal/Frontal Branch

Function: Frontalis, superior orbicularis

Critical zone: Zygomatic arch

High Risk

Zygomatic Branch

Function: Orbicularis oculi

Critical zone: Protected by SMAS

Medium Risk

Buccal Branch

Function: Lip elevators, zygomaticus

Critical zone: Midface - highest attention

High Risk

Marginal Branch

Function: Lip depressors

Critical zone: Mandibular border

Very High Risk

Cervical Branch

Function: Platysma

Critical zone: Neck

Low Risk

⚠️ The Marginal Branch

The marginal mandibular branch is responsible for most complications in facial surgery. Its injury causes lip asymmetry — the "crooked smile" that identifies surgical complication.

  • •Crosses mandible at variable position
  • •In 20% of cases, passes below inferior mandibular border
  • •Direct vision allows identification before injury

Trigeminal (V) — Sensory Branches

Supraorbital

V1

Area: Forehead and anterior scalp

Supratrochlear

V1

Area: Glabella and medial forehead

Infraorbital

V2

Area: Lower eyelid, lateral nose, upper lip

Mental

V3

Area: Lower lip and chin

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