The facial vein is ligated and divided well below the margin of the mandible to avoid damage to the marginal branch of the facial nerve which may descend two centimeters or more. Lifting up the vein elevates the nerve which lies superficial to it and keeps it out of harm's way. The facial artery emerges from beneath the gland closer to the mandibular border and may not be safely divided with the vein at this early stage.
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