title: Physiological cross-sectional area of the oblique head of the adductor pollicis is greater than its transverse counterpart: implications for functional testing.
abstract: BACKGROUND
  Despite structural distinction between the transverse and oblique heads of the adductor pollicis, in vivo testing continues to consider the adductor pollicis as functionally simplistic. As a muscle's architecture is a strong indicator of function, in this study we aimed to determine whether the physiological cross-sectional areas (PCSAs) of both heads were uniform.
  
  
  METHODS
  Classical, microdissection, and chemical dissection procedures were conducted on 10 cadaveric left hands to determine structural origin and insertions. Architectural measures of muscle length (Lm ), muscle weight (Wm ), fascicle length (Lf ), sarcomere length (Ls ), and pennation angle (θ) were used to calculate PCSA and fascicle length:muscle length ratio (Lf :Lm ).
  
  
  RESULTS
  The oblique head had greater variation in attachments, significantly greater PCSA (P = 0.008), and smaller Lf :Lm (P = 0.001) than its transverse counterpart.
  
  
  CONCLUSIONS
  Muscle architecture suggests the oblique head has greater potential for force generation, and the transverse has greater potential for joint excursion.
authors.affiliation: Neural Control of Movement Laboratory, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, New South Wales, Australia; Biomechanics Research Laboratory, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, New South Wales, Australia; Human Anatomy Laboratory, Faculty of Science, Medicine and Health, University of Wollongong, Northfields Avenue, Wollongong, New South Wales, 2522, Australia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Stamenkovic
authors.forename: Bridget J
authors.initials: BJ
authors.lastname: Munro
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Peoples
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D006225:Hand / Q000294:innervation; D006801:Humans; D008297:Male; D042282:Microdissection; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000502:physiology*; D009929:Organ Size / Q000502:physiology; D013314:Stress, Mechanical
keywords: adductor pollicis; hand; muscle architecture; muscle function; physiological cross-sectional area