title: Variations in the distance between the cricoid cartilage and targets of stellate ganglion block in neutral and extended supine positions: an ultrasonographic evaluation.
abstract: Anatomic variations complicate surface landmark-guided needle placement, thereby increasing nerve blockade failure rate. However, little is understood about how anatomic distances change under different clinical conditions. As the cricoid cartilage is an easy and accurate landmark, we investigated changes in distance between the sixth or seventh cervical transverse processes (C6TP or C7TP) and the cricoid cartilage in neutral and extended supine positions.
  
  
  
  Forty-two patients (16 men, 26 women) were included in this study. Distances between the cricoid cartilage and C6TP/C7TP were measured using ultrasonography with the patient in neutral and extended supine positions.
  
  
  
  C6TP and C7TP were caudally located at 6.0 ± 8.1 and 15.1 ± 7.2 mm, respectively, from the cricoid cartilage in the neutral supine position, and at 15.2 ± 8.0 and 25.3 ± 8.0 mm, respectively, in the extended supine position. In the extended supine position, the cricoid cartilage was more cephalad than C6TP and C7TP in all patients. The distance from the cricoid cartilage to C6TP was 12.1 ± 7.6 mm in men and 17.2 ± 7.7 mm in women.
  
  
  
  C6TP and C7TP are located approximately 15 and 25 mm, respectively, caudal to the cricoid cartilage in the extended supine position. Our results highlight the fact that there can be significant anatomic variation between the extended and neutral supine positions used in stellate ganglion block, which should be kept in mind when devising easily identifiable and palpable surface landmarks.
authors: Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Gangnam Severance Hospital, College of Medicine, Yonsei University, Seoul, Korea.
authors: Jiwon
authors: J
authors: An
authors: Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Gangnam Severance Hospital, College of Medicine, Yonsei University, Seoul, Korea.
authors: Youn-Woo
authors: YW
authors: Lee
authors: Department of Anesthesia, Sheikh Khalifa Specialty Hospital, Ras Al Khaimah, United Arab Emirates.|Department of Anesthesiology and Pain Medicine, College of Medicine, Seoul National University, Seoul, Korea.
authors: Woo Young
authors: WY
authors: Park
authors: Department of Anesthesiology and Pain Medicine, College of Medicine, Ajou University, San 5, Wonchon-dong, Yeongtong-gu, Suwon, 443-721, Korea.
authors: Sungchul
authors: S
authors: Park
authors: Department of Anesthesiology and Pain Medicine, College of Medicine, Ajou University, San 5, Wonchon-dong, Yeongtong-gu, Suwon, 443-721, Korea.
authors: Hyungbae
authors: H
authors: Park
authors: Department of Internal Medicine, School of Medicine, University of Nevada, Las Vegas, NV, USA.
authors: Ji Won
authors: JW
authors: Yoo
authors: Department of Anesthesiology and Pain Medicine, College of Medicine, Ajou University, San 5, Wonchon-dong, Yeongtong-gu, Suwon, 443-721, Korea. romeojb@naver.com.
authors: Jong Bum
authors: 0000-0003-2277-1095
authors: JB
authors: Choi
mesh_terms: D000328:Adult; D000368:Aged; D001340:Autonomic Nerve Block / Q000379:methods*; D002574:Cervical Vertebrae; D003413:Cricoid Cartilage / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013233:Stellate Ganglion / Q000033:anatomy & histology*; D016683:Supine Position
keywords: Cricoid cartilage; Stellate ganglion block; Transverse process