title: Increased reflectivity and loss in bulk of the pronator quadratus muscle does not always indicate anterior interosseous neuropathy on ultrasound.
abstract: OBJECTIVE
  To assess if isolated atrophy of the pronator quadratus muscle indicates anterior interosseous neuropathy on ultrasound.
  
  
  METHODS
  IRB approval and written informed from every patient were obtained. A prospective study including 100 consecutive wrist and hand ultrasound studies in 77 patients (46 females and 31 males; 23 patients had bilateral studies) with a mean age of 45 years (range, 21-86 years) was performed between March 2010 and January 2012. The patients were chosen irrespective of age, sex, and body mass index. The studies were performed for several reasons, the most common being wrist pain (n=56), followed by ganglion cyst (n=11) and soft-tissue masses (n=10). Clinical histories, previous imaging studies and US examinations were evaluated to rule out anterior interosseous nerve neuropathy. US examinations were performed with a commercially available equipment. Pronator quadratus was checked for atrophy using flexor pollicis longus, flexor digitorum superficialis and profundus for comparison. Descriptive statistic was used.
  
  
  RESULTS
  US signs of pronator quadratus atrophy were present in 7/100 (7%) of patients. None of the patients had a bilateral atrophy of the pronator quadratus. In the patients with atrophy of the pronator quadratus, adjacent flexor muscles were normal. There was no significant difference between males and females (3 females vs 4 males) (p=0.506).
  
  
  CONCLUSIONS
  Increased reflectivity and loss in bulk of the pronator quadratus muscle does not always indicate anterior interosseous neuropathy on ultrasound.
authors.affiliation: Department of Human Anatomy, DIMES, Università di Genova, Largo Rosanna Benzi 8, 16138 Genoa, Italy. albertotagliafico@gmail.com
authors.forename: Alberto
authors.initials: A
authors.lastname: Tagliafico
authors.forename: Maribel Miguel
authors.initials: MM
authors.lastname: Perez
authors.forename: Luca
authors.initials: L
authors.lastname: Padua
authors.forename: Andrea
authors.initials: A
authors.lastname: Klauser
authors.forename: Antonio
authors.initials: A
authors.lastname: Zicca
authors.forename: Carlo
authors.initials: C
authors.lastname: Martinoli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005542:Forearm / Q000000981:diagnostic imaging* / Q000294:innervation*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging*; D009408:Nerve Compression Syndromes / Q000000981:diagnostic imaging*; D009929:Organ Size; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult