title: Diaphragm depth in normal subjects.
abstract: BACKGROUND
  Needle electromyography (EMG) of the diaphragm carries the potential risk of pneumothorax. Knowing the approximate depth of the diaphragm should increase the test's safety and accuracy.
  
  
  METHODS
  Distances from the skin to the diaphragm and from the outer surface of the rib to the diaphragm were measured using B mode ultrasound in 150 normal subjects.
  
  
  RESULTS
  When measured at the lower intercostal spaces, diaphragm depth varied between 0.78 and 4.91 cm beneath the skin surface and between 0.25 and 1.48 cm below the outer surface of the rib. Using linear regression modeling, body mass index (BMI) could be used to predict diaphragm depth from the skin to within an average of 1.15 mm.
  
  
  CONCLUSIONS
  Diaphragm depth from the skin can vary by more than 4 cm. When image guidance is not available to enhance accuracy and safety of diaphragm EMG, it is possible to reliably predict the depth of the diaphragm based on BMI.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Mayo Clinic and Foundation, Rochester, Minnesota, 55905, USA.
authors.forename: Leili
authors.initials: L
authors.lastname: Shahgholi
authors.forename: Michael R
authors.initials: MR
authors.lastname: Baria
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Sorenson
authors.forename: Caitlin J
authors.initials: CJ
authors.lastname: Harper
authors.forename: James C
authors.initials: JC
authors.lastname: Watson
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Strommen
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Boon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D003964:Diaphragm / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D004576:Electromyography / Q000009:adverse effects; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011030:Pneumothorax / Q000209:etiology / Q000517:prevention & control; D012016:Reference Values; D012189:Retrospective Studies; D014463:Ultrasonography; D055815:Young Adult
keywords: BMI; depth; diaphragm; electromyography; ultrasound