Department of Pain Management Xuanwu Hospital of Capital Medical University Beijing 100053 ChinaDepartment of Anesthesiology and Pain Medicine Aviation General Hospital of China Medical University Beijing Institute of Translational Medicine Chinese Academy of Sciences Beijing 100012 China;
Department of Pain Management Xuanwu Hospital of Capital Medical University Beijing 100053 China;
Department of Pain Management Xuanwu Hospital of Capital Medical University Beijing 100053 China;
Department of Pain Management Xuanwu Hospital of Capital Medical University Beijing 100053 ChinaDepartment of Anesthesiology and Pain Medicine Aviation General Hospital of China Medical University Beijing Institute of Translational Medicine Chinese Academy of Sciences Beijing 100012 China;
Department of Pain Management Xuanwu Hospital of Capital Medical University Beijing 100053 ChinaDepartment of Anesthesiology and Pain Medicine Aviation General Hospital of China Medical University Beijing Institute of Translational Medicine Chinese Academy of Sciences Beijing 100012 China;
Department of Pain Management Xuanwu Hospital of Capital Medical University Beijing 100053 China;
Preprocedure ultrasound imaging; Epidural puncture; Epidural catheterization; Palpation technique; Labor analgesia;