title: The caudal space in fetuses: an anatomical study.
abstract: OBJECTIVE
  The caudal epidural space is a popular site for analgesia in pediatrics. High variation in blind needle placement is common during caudal epidurals, increasing the risk of intravascular and intrathecal spread. Knowledge of safe distances and angles for accessing the caudal epidural space in premature infants can improve the safety of caudal epidural blocks.
  
  
  METHODS
  Thirty-nine fetuses with crown-heel length between 33 and 50 cm, corresponding to gestational age of 7-9 months, were included. The dorsal surface of the sacrum from the fourth lumbar vertebra to the tip of the coccyx was dissected, following which measurements were taken on dorsal surface and midsagittal sections. The angle of depression of the needle was measured using a goniometer following the two-step method of needle insertion.
  
  
  RESULTS
  Right and left sacral cornua were palpable in 23 of 39 fetuses (58.97%). Termination of dural sac was at S2 in most of the fetuses (53.84%), whereas the apex of the sacral hiatus was at S3 in most (58.97%). The distance from the apex of the hiatus to the termination of dura ranged from 3 to 13 mm; the anteroposterior distance of the canal at the apex of the hiatus ranged from 1.72 to 4.38 mm. All sacral parameters correlated with crown-heel length except inter-cornual distance, depth of canal at hiatus, and height of sacral hiatus.
  
  
  CONCLUSIONS
  Distances and angles for accessing the caudal epidural space in fetuses do not provide all parameters for safe performance of caudal epidural blocks in premature and low birth weight infants because the apex of the sacral hiatus and the termination of the dura show wide variation in location.
authors.affiliation: Department of Anatomy, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Anjali
authors.initials: A
authors.lastname: Aggarwal
authors.forename: Daisy
authors.initials: D
authors.lastname: Sahni
authors.forename: Harjeet
authors.initials: H
authors.lastname: Kaur
authors.forename: Yatindra K
authors.initials: YK
authors.lastname: Batra
authors.forename: Rakesh
authors.initials: R
authors.lastname: Sondekoppam Vijayashankar
mesh_terms: D000763:Anesthesia, Caudal / Q000379:methods*; D000767:Anesthesia, Epidural / Q000295:instrumentation / Q000379:methods*; D002102:Cadaver; D003050:Coccyx / Q000033:anatomy & histology; D004824:Epidural Space / Q000033:anatomy & histology*; D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D008297:Male; D009339:Needles; D012447:Sacrum / Q000033:anatomy & histology
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