title: A study of the anatomy of the caudal space using magnetic resonance imaging.
abstract: We have studied, in 37 adult patients, the anatomy of the sacral extradural (caudal) space using magnetic resonance imaging. The sacrococcygeal membrane (SCM) could not be detected in 10.8% of patients. The maximum depth of the caudal space adjacent to the SCM was beneath the upper third of the SCM in more than 90% of patients (mean depth 4.6 mm; range 1.0-8.0 mm). The shortest linear distance from the dura to the upper limit of the SCM varied considerably (60.5 mm; 34-80 mm) as did the volume of the caudal space excluding the foraminae and dural sac (14.4 cm3; 9.5-26.6 cm3). The dimensions of the caudal space and their variability have implications for clinical practice and a knowledge of these dimensions may increase both the reliability and safety of caudal techniques in adult patients.
authors.affiliation: Queen's Medical Centre, Nottingham.
authors.forename: I M
authors.initials: IM
authors.lastname: Crighton
authors.forename: B P
authors.initials: BP
authors.lastname: Barry
authors.forename: G J
authors.initials: GJ
authors.lastname: Hobbs
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015360:Analgesia, Epidural; D000763:Anesthesia, Caudal; D000886:Anthropometry; D004824:Epidural Space / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012447:Sacrum / Q000033:anatomy & histology