Table 1.

The summary of differences between osteocytic and anosteocytic bone.

Character	Osteocytic bone	Anosteocytic bone	Reference
Microscopic gross structure	Hierarchical Haversian systems circled by secondary osteons.	Featureless at low magnifications and lamellated at higher magnifications with tubules traversing the lamella. (Specimen: Tilapia) Clearly demarcated overlapped hypermineralized remodeling rings and higher osteonal density (Specimen: Billed fish).	(47, 50)
Mechanical properties	Higher stiffness measured by nanoindentation and three-point bending tests (Human)	Higher toughness or more compliant (Tilapia)	(47, 49)
Porosity levels	Connected Haversian canals LCN Nanoporosities for water (between the collagen and the mineral and around the fibrils)	Lower porosity than osteocytic bone with tubular structures packed with collagen. Surface osteoblastic processes occupying canals of Williamson Nano porosities for water (Tilapia) Central cavity delineated by remodeling lines and off-center transverse vascular porosities with higher porosity than osteocytic bone (Billed fish)	(49, 50)
Remodeling potential	Modeling and remodeling occur throughout life.	Increases in load demand (water currents and hard diets) during intensive growth periods. Intense remodeling in billed fish (such as blue marlin) resembling secondary osteons.	(49, 50)
Osteoclasts	Mononucleated devoid of ruffled borders (osteocytic fish) Multinucleated with ruffled borders (mammals)	Mononucleated and devoid of ruffled borders	(41)
Osteoblasts	Present	Present	(41)