title: Cross-sectional sonographic assessment of the posterior interosseous nerve.
abstract: OBJECTIVE
  Cross-sectional sonographic measurements are considered first-line confirmatory tests in diagnosing peripheral nerve entrapment syndromes. Our aim is to establish normal values of cross-sectional area of the posterior interosseous nerve (PIN) at the arcade of Frohse, the most common site of compression of this nerve.
  
  
  METHODS
  The PIN was identified with ultrasound on 50 healthy adults and 30 cadavers. Measurements of the cross-sectional area (CSA), antero-posterior (AP) and lateral (L) distances were taken immediately proximal and distal to the arcade of Frohse.
  
  
  RESULTS
  The mean AP and L distances of the PIN proximal to the arcade of Frohse were 0.111 cm (0 ± 0.021) and 0.266 cm (±0.058), respectively, while the mean AP and L distances of the PIN distal to the arcade of Frohse were 0.085 cm (±0.019) and 0.343 cm (±0.057), respectively. P squared testing showed a statistically significant difference between the AP and lateral distances of the PIN when comparing proximal and distal to the arcade (p ≤ 0.001). However, the mean CSA of the PIN measured immediately proximal to the arcade of Frohse was 0.022 cm(2) (±0.005); immediately distal to the arcade of Frohse, it was 0.023 cm(2) (±0.004). t test showed no statistical difference between the two regions (p = 0.11).
  
  
  CONCLUSIONS
  Our study has provided reference values for the PIN in healthy individuals at the arcade of Frohse. Although, there is a flattening of the nerve as it enters the supinator muscle, this should not be mistaken for nerve entrapment as the size of the nerve remains consistent.
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St. George's University, St. George's, Grenada, West Indies.
authors.forename: Kazzara
authors.initials: K
authors.lastname: Raeburn
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St. George's University, St. George's, Grenada, West Indies.
authors.forename: Danny
authors.initials: D
authors.lastname: Burns
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St. George's University, St. George's, Grenada, West Indies.
authors.forename: Robert
authors.initials: R
authors.lastname: Hage
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St. George's University, St. George's, Grenada, West Indies.|Pediatric Neurosurgery, Children's Hospital of Alabama, Birmingham, AL, USA.
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St. George's University, St. George's, Grenada, West Indies. mloukas@sgu.edu.
authors.forename: Marios
authors.initials: M
authors.lastname: Loukas
mesh_terms: D000328:Adult; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000000981:diagnostic imaging*; D010525:Peripheral Nerves / Q000000981:diagnostic imaging*; D013577:Syndrome; D014463:Ultrasonography; D034941:Upper Extremity / Q000000981:diagnostic imaging / Q000294:innervation; D055815:Young Adult
keywords: Arcade of Frohse; Peripheral nerve entrapment; Posterior interosseous nerve (PIN); Posterior interosseous nerve syndrome; Ultrasound of posterior interosseous nerve