Osteocyte Lacunae are Lenticular/Ellipsoid Spaces or Spiral/Helical Tubules

Abstract

Introduction: According to the current concept of bone structure, the osteocyte lacunae are lenticular or ellipsoid spaces occupied by osteocytes. These osteocytes are thought to communicate with each other through a tubular system made up of Canaliculi. The rest of the structures i.e., Haversian canal, and Volkmann’s canal are also tubular in shape. Considering this existing concept of bone microstructure described by various authors, it is highly unlikely that the lacunae alone would be lenticular/ellipsoid structure. In the present study author wanted to know that amongst the all tubular spaces, what is the reason that only the osteocyte lacunae are lenticular or ellipsoid structure? Also to investigate whether these lenticular spaces are really lenticular/ellipsoid or they are cut sections of tubes, which are lying helically or spirally. It is well known from various previous studies that Haversian canal, Volkmann’s canal and Canaliculi are tubular shaped structures and how it is possible that lenticular/ellipsoid structure can present amongst them. So we thought that, it may be possible that these lenticular spaces are not actually lenticular but this lenticular shape is due to the cut sections of any type of tubule in various possible planes (i.e., transverse, longitudinal and various degrees of oblique plane). Aim: The present study was carried out to reinvestigate the shape of the osteocyte lacunae amongst the tubular system (i.e., Haversian canal, Volkmann’s canal and Canaliculi) of compact bone. Materials and Methods: The study is carried out by preparing thin sections of adult bones (ground glass preparation) and visualizing them under binocular light microscope and scanelectron microscope after following proper procedure. Results: We observed that the lacunae are actually spirally/helically placed tubules with several branching. These branching are considered as canaliculi. These branching are of various diameters and they anastomose between themselves. It does appear that the so called osteocyte lacunae are optical illusions in the light microscope representing the depth of the lumen of these tubular spaces, which get sectioned in all possible planes. Conclusion: From the present study we concluded that the whole structure of mature bone is tubular in shape without the presence of lenticular/ellipsoid lacunae. The transport of organic and inorganic material may be by free flow mechanism through this tubular framework. We hope that this fresh understanding of basic bone structure will open new vistas for further research.

Keywords

• Canaliculi
• Haversian canal
• Lamellae
• Volkmann’s Canal