title: Morphologic characteristics of sacra associated with assimilation of the last lumbar vertebra.
abstract: BACKGROUND
  The impact of lumbosacral transitional states on biomechanics of load transmission between the spine and the legs has been sporadically reported. The aims of the study were to identify morphostructural alterations of sacra associated with assimilation of the last lumbar vertebra and to analyse them in the light of their biomechanical impact.
  
  
  METHODS
  Linear dimensions of sacrum, its body and base and articular surfaces were measured in 31 normal and 41 transitory sacra. Nineteen sacra presented articular and 22 osseous fusion of the last lumbar vertebra. Measured parameters were compared between normal sacra and the two variations of transitory sacra.
  
  
  RESULTS
  Sacra with articular fusion of the last lumbar vertebra showed more pronounced concavity of the sacral curvature and wider than long sacral bodies. The first sacral segment was modified, broaden, ventrally wider and elevated. Almost the whole segment bore at its sides auricular surfaces. Very small portion of the segment was non-articular with less pronounced wedging. Sacra with osseous fusion of the last lumbar vertebra showed similar concavity of the sacral curvature as normal sacra, but longer than wide sacral bodies. The ventral sloping half of the newly formed first segment bore auricular surfaces. The non-articular part was enlarged with pronounced wedging.
  
  
  CONCLUSIONS
  The term "sacralisation" includes both types of transitory sacra with mutually different morphostructural characteristics in contrast to the normal sacra. Analysis of these morphologic variations may help in understanding the different biomechanical properties and patterns of load transmission.
authors.affiliation: University "Ss. Cyril and Methodius", Faculty of Medicine, Institute of Anatomy, Skopje, R. Macedonia. nikimatveeva@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Matveeva
authors.forename: M
authors.initials: M
authors.lastname: Papazova
authors.forename: J
authors.initials: J
authors.lastname: Zhivadinovik
authors.forename: B
authors.initials: B
authors.lastname: Zafirova
authors.forename: A
authors.initials: A
authors.lastname: Dodevski
authors.forename: V
authors.initials: V
authors.lastname: Poposka
mesh_terms: D007596:Joints; D008159:Lumbar Vertebrae; D008161:Lumbosacral Region; D012447:Sacrum
keywords: auricular surface; lumbosacral transitory vertebra; sacralisation; sacroiliac joints