[Regional Anatomy] Skin→subcutaneous tissue→between the left and right trapezius muscle →nuchal ligament (between the left and right splenius muscles of head→between the left and right semispinal muscles of head). Superficial layer, the third occipital nerve, and the subcutaneous vein; deep layer, the branch of the posterior rami of the second and third cervical nerves, the external (posterior) vertebral venous plexus and the branches or tributaries of the occipital artery and vein.