How to divide cervical lymph nodes

The cervical lymph nodes can be divided into seven regions, including chin and mandible, submandibular lymph nodes as region 1, superior internal jugular vein lymph nodes as region 2, middle internal jugular vein lymph nodes as region 3, inferior internal jugular vein lymph nodes as region 4, posterior jugular triangular lymph nodes as region 5, central lymph nodes as region 6, superior mediastinal lymph nodes as region 7.