title: The cross-sectional area changes in digital flexor tendons and suspensory ligament in foals by ultrasonographic examination.
abstract: BACKGROUND
  Flexural deformities are common conditions of growing horses and are suggested to have a relationship with the contraction of musculotendinous units. However, limited studies have documented the changes in each tendon and ligament in the metacarpal region with age.
  
  
  OBJECTIVE
  To investigate the changes in the cross-sectional area (CSA) of each tendon and ligament in the metacarpal region with age by ultrasonographic examination.
  
  
  METHODS
  Longitudinal study of foals from Day 1 to age 24 months.
  
  
  METHODS
  The CSA of the superficial digital flexor tendon, deep digital flexor tendon, accessory ligament of the deep digital flexor tendon and suspensory ligament was measured by ultrasonographic examination at monthly intervals from Day 1 to age 24 months in 7 Thoroughbred foals.
  
  
  RESULTS
  Changes in superficial digital flexor CSA in all regions were larger than those of other structures from 10 months to 15 months. The suspensory ligament CSA was significantly larger than those of other structures on Day 1 in both the region of suspensory origin (RSO) and region of suspensory body (RSBO). This condition continued until 2 months in the RSO and until 5 months in the RSBO. The changes in deep digital flexor CSA were larger than those of other structures from 2 to 5 months in both the RSO and RSBO.
  
  
  CONCLUSIONS
  The rate of change in each structure varies with age. Thus, the functional adaptation with age that takes place may differ among structures because the primary function of each structure differs.
authors.affiliation: Hidaka Training and Research Center, Japan Racing Association, Urakawa-gun, Hokkaido, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Korosue
authors.affiliation: Hidaka Training and Research Center, Japan Racing Association, Urakawa-gun, Hokkaido, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Endo
authors.affiliation: Hidaka Training and Research Center, Japan Racing Association, Urakawa-gun, Hokkaido, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Murase
authors.affiliation: Hidaka Training and Research Center, Japan Racing Association, Urakawa-gun, Hokkaido, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ishimaru
authors.affiliation: Hidaka Training and Research Center, Japan Racing Association, Urakawa-gun, Hokkaido, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nambo
authors.affiliation: Hidaka Training and Research Center, Japan Racing Association, Urakawa-gun, Hokkaido, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Sato
mesh_terms: D000375:Aging; D000818:Animals; D005260:Female; D005552:Forelimb / Q000000981:diagnostic imaging; D006736:Horses / Q000254:growth & development*; D008022:Ligaments / Q000000981:diagnostic imaging* / Q000254:growth & development*; D008297:Male; D013710:Tendons / Q000000981:diagnostic imaging* / Q000254:growth & development*; D014463:Ultrasonography
keywords: conformation change; distal limb; foal; horse; radiographic evaluation