Retraction of the corner of the mouth by an assistant

Reproduced with permission from: Murphy MP, Barker TD, Schneider RE. Endotracheal intubation. In: Manual of Emergency Airway Management, 3rd ed, Walls RM, Murphy MF (Eds), Lippincott Williams & Wilkins, Philadelphia 2008. Copyright © 2008 Lippincott Williams & Wilkins. www.lww.com.