Fig. 9

Lateral neck selective (level IIa–IV) lymph node dissection. A Free posterior edge of sternocleidomastoid muscle. B The internal jugular vein was exposed by free cervical sheath. C Free and retain the scapulohyoid muscle. D Dissection of lymph nodes in Area IV. E Dissection of lymph nodes in Zone III. F Implant a pull hook to pull the internal jugular vein. G Dissection of lymph nodes in Area IIa. H Expose the digastric muscle. I Operation area after lymph node dissection of right cervical region IIa–IV