title: Distal border synovial invaginations of the equine distal sesamoid bone communicate with the distal interphalangeal joint.
abstract: OBJECTIVE
  Macroscopic studies have suggested a link between distal border synovial invaginations of the navicular bone and the distal interphalangeal joint. However, many practitioners consider that these invaginations are directly and solely related to navicular disease. The objective was to investigate the communication pattern of these synovial invaginations with the synovial compartments of the distal interphalangeal joint and the navicular bursa, using minimally invasive imaging techniques.
  
  
  METHODS
  In a prospective observational study, 10 cadaveric limbs with radiographically evident distal border synovial invaginations were randomly assigned to computed tomography arthrography or bursography groups, using iopamidol.
  
  
  RESULTS
  In 5/5 limbs, contrast medium filled the invaginations following distal interphalangeal arthrography. In the other five limbs, no contrast medium filled the invaginations following bursography.
  
  
  CONCLUSIONS
  Contrary to existing beliefs, these invaginations are more likely associated with distal interphalangeal joint synovitis and may not be directly linked to primary navicular bone pathology, but might reflect distal interphalangeal arthropathy. Therefore, the rationale for assessment of these invaginations in stallion selection or pre-purchase examinations as a predictive sign for navicular disease is questionable. Nonetheless, comorbidities are frequent in the equine distal limb. Enlarged synovial invaginations may also be seen in limbs with concomitant primary navicular disease. Further studies are needed to elucidate possible inter-related pathological processes.
authors.affiliation: Dr. Julien Olive, Département de Sciences Cliniques, Centre Hospitalier Universitaire Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, J2S 7C6, Canada.
authors.forename: Julien
authors.initials: J
authors.lastname: Olive
authors.forename: Marine
authors.initials: M
authors.lastname: Videau
mesh_terms: D000818:Animals; D002061:Bursa, Synovial / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006724:Hoof and Claw / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006736:Horses / Q000033:anatomy & histology*; D007596:Joints / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D011446:Prospective Studies; D012716:Sesamoid Bones / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D013583:Synovial Membrane / Q000000981:diagnostic imaging; D013643:Tarsus, Animal / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000662:veterinary
keywords: Horse; arthrography; bursography; navicular bone