title: Is there a characteristic distal tarsal subchondral bone plate thickness pattern in horses with no history of hindlimb lameness?
abstract: BACKGROUND
  Osteoarthritis (OA) is a common cause of distal tarsal pain, but disease development is poorly understood. Awareness of normal tarsal structure and function is important in order to understand the pathogenesis of OA. Thickening of the subchondral bone (SCB) plate has been related to the development of OA, but SCB plate patterns in the equine tarsus have not been documented.
  
  
  OBJECTIVE
  There is a repeatable pattern of SCB thickness across the distal tarsal joints, and specifically that thickness would be greatest dorsally and laterally.
  
  
  METHODS
  Twenty cadaver tarsi were collected from mature horses that had undertaken low-level exercise only with no history of hindlimb lameness. Magnetic resonance images were acquired using a high-resolution sagittal 3-dimensional T1-weighted spoiled gradient echo sequence. Subchondral bone thickness was measured on sagittal images at dorsal and plantar locations on the proximal and distal aspects of the central (CT) and third (T3) tarsal bones and proximal aspect of the third metatarsal bone (Mt3).
  
  
  RESULTS
  On the proximal aspect of CT, medial and lateral SCB thickness were significantly greater than midline. On the distal aspect of CT and T3 and proximal Mt3, lateral SCB thickness was significantly greater than medial and midline sites. Dorsal SCB thickness was greatest on the proximal and distal aspects of CT and proximal Mt3. Subchondral bone accounted for a greater proportion of CT and T3 on the dorsal aspect than the plantar.
  
  
  CONCLUSIONS
  There is a repeatable pattern of SCB thickness in the distal tarsal bones of horses with no history of hindlimb lameness. This reflects the pattern of loading across the joints.
  
  
  CONCLUSIONS
  This study provides evidence of a consistent osteochondral pattern in the equine tarsus for reference in identification of osteoarticular pathologies.
authors.affiliation: Centre for Equine Studies, The Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK.
authors.forename: M V
authors.initials: MV
authors.lastname: Branch
authors.forename: R C
authors.initials: RC
authors.lastname: Murray
authors.forename: S J
authors.initials: SJ
authors.lastname: Dyson
authors.forename: A E
authors.initials: AE
authors.lastname: Goodship
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology; D002102:Cadaver; D005260:Female; D006614:Hindlimb; D006734:Horse Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D006736:Horses / Q000033:anatomy & histology* / Q000502:physiology; D007794:Lameness, Animal / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000662:veterinary; D008297:Male; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000473:pathology / Q000662:veterinary; D011859:Radiography; D013640:Tarsal Joints / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D013643:Tarsus, Animal / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*