Pazzaglia Ugo E, Bonaspetti Giovanni, Rodella Luigi F, Ranchetti Federico, Azzola Flavio
Clinica Ortopedica, Università di Brescia, Italy.
J Anat. 2007 Sep;211(3):303-12. doi: 10.1111/j.1469-7580.2007.00782.x.
The architecture of the diaphyseal bone is closely correlated with the cortical vessel network, whose pattern develops in the course of growth. Various methods have been applied to clarify the three-dimensional anatomy of the cortical canal system, but there is still disagreement about the geometry, blood supply, flux dynamics and factors controlling canal geometry during bone growth and remodeling. A modification of the currently employed dye-injection method was applied to study the vessel network of the whole hemi-shaft of the rabbit femur in mature bones (8-month-old rabbits) and growing bones (1.5-month-old rabbits). The cortical vascular tree of the hemi-shaft of the femur was injected with black China ink and observed in full-thickness specimens of the cortex. The same specimens were then processed for histology. A comparative study of the middle diaphysis (mid-shaft) with the distal extremity (distal shaft) was performed in both young and old rabbit femurs. The longitudinally oriented pattern of the vessel network was seen to develop in the diaphysis of mature femurs, while at the extremity of the shaft of the same specimen the network showed a reticular organization without a dominant polarization. The vessels were significantly higher in the mid-shaft than in the distal shaft of the old femurs (P < 0.0001), as was their diameter (P < 0.05). In the group of young rabbits at mid-shaft level the longitudinally oriented pattern of the vessel network was not yet completely developed, without their being significant differences in length and diameter between the mid-shaft and distal shaft. The differentiation of the mid-shaft from the distal shaft was confirmed histologically by the presence, in the latter, of longitudinal calcified cartilage septa between osteons. This pattern of structural organization and development of the intracortical vascular network has not been previously reported. The cells primarily involved in polarization of the remodeling process were the osteoclasts at the top of the cutting cones advancing from the proximal and distal metaphyses toward the mid-shaft. This suggests, first, a relationship with the longitudinally oriented structures already present in the cortex near the metaphysis (the calcified cartilage septa) and then with the columns of interosteonic breccia, which were formed as a secondary effect of the longitudinal polarization of the remodeling process. Our observations did not enable us to substantiate the model of two different systems, one of longitudinal vessels (Havers) and the other of connecting transversal vessels (Volkmann), but suggested instead that there is a network whose loops lengthen in the direction of the major bone axis in the course of growth and secondary modeling. The associated morphology supported the view that the type of structural organization of the tubular bone cortex is primarily determined by an inherited constitutional factor rather than by mechanical strains.
骨干骨的结构与皮质血管网络密切相关，其模式在生长过程中形成。人们已应用各种方法来阐明皮质管系统的三维解剖结构，但对于骨生长和重塑过程中管的几何形状、血液供应、通量动力学以及控制管几何形状的因素仍存在分歧。我们对当前使用的染料注射法进行了改进，以研究成熟骨（8月龄兔）和生长骨（1.5月龄兔）中兔股骨整个半侧骨干的血管网络。向股骨半侧骨干的皮质血管树注射中国墨汁，并在皮质的全层标本中进行观察。然后对相同标本进行组织学处理。在幼年和老年兔股骨中对骨干中部（中段）与远端（远段）进行了对比研究。在成熟股骨的骨干中可见血管网络呈纵向排列模式，而在同一标本骨干的末端，网络呈网状组织，无明显的极化现象。老年股骨中段的血管数量显著高于远段（P < 0.0001），其直径也是如此（P < 0.05）。在幼年兔组的中段水平，血管网络的纵向排列模式尚未完全形成，中段和远段之间在长度和直径上无显著差异。组织学证实，远段骨干与中段骨干的差异在于，远段骨单位之间存在纵向钙化软骨间隔。这种皮质内血管网络的结构组织和发育模式此前未见报道。参与重塑过程极化的主要细胞是破骨细胞，它们位于从近端和远端干骺端向中段推进的切割锥顶部。这首先表明与干骺端附近皮质中已存在的纵向结构（钙化软骨间隔）有关，然后与骨间角砾岩柱有关，骨间角砾岩柱是重塑过程纵向极化的次生效应形成的。我们的观察结果无法证实两种不同系统的模型，一种是纵向血管（哈弗斯血管）系统，另一种是连接横向血管（福尔克曼血管）系统，而是表明存在一个网络，其环在生长和二次塑形过程中沿主要骨轴方向延长。相关形态学支持了这样一种观点，即管状骨皮质的结构组织类型主要由遗传体质因素而非机械应变决定。
