Department of Veterinary Clinical Medicine, School of Veterinary Medicine, Faculty of Agriculture, Tottori University, Tottori, Japan.
J Dairy Sci. 2012 Jan;95(1):127-38. doi: 10.3168/jds.2011-4316.
Computed tomography (CT) was performed on 400 claws (200 inner and 200 outer claws) of 100 pairs of bovine hind limbs to investigate the etiological theory that an exacerbating factor for ulceration is exostosis of the tuberculum flexorium within the distal phalanx. A variety of morphological changes of the tuberculum flexorium of bovine hind limb claws was visualized by 3-dimensional CT, and the geometry of these claws suggested a growth pattern of bone development with respect to the assumed daily loading patterns. This growth occurs initially at the abaxial caudal aspect of the distal phalanx and is followed by horizontal progression toward the axial aspect. The length of downward bone development on the solar face of the distal phalanx was 2.73±1.32 mm in the outer claws, significantly greater than in the inner claws (2.38±0.96 mm). Ratios of downward (vertical) bone development to the thickness of the subcutis and the corium (VerBD ratios) did not differ between the outer and inner claws (36.7 vs. 38.3%, respectively). Ratios of horizontal bone development to the axial-to-abaxial line of the tuberculum flexorium (HorBD ratios) were approximately 60% for both outer and inner claws. These quantitative measures regarding horizontal and vertical bone development within the distal phalanx were positively correlated with age and VerBD ratios (r=0.53 and r=0.36 for the inner and outer claws, respectively). Correlations between claw width of the outer claw and length of vertical bone development (r=0.43), the HorBD ratio (r=0.51), and the VerBD ratio (r=0.42) suggested that the relative size difference between the inner and outer claws enhances bone development in the outer claw. Correlation coefficients between VerBD and HorBD ratios (r=0.52 and 0.63 for the inner and outer claws, respectively) suggested that horizontal and vertical bone development occurs as a synchronized process within the tuberculum flexorium. This age-related progress of bone development within the tuberculum flexorium is associated with increased exposure to several exacerbating factors and the laminitic process.
对 100 对牛后肢的 400 个爪子（200 个内爪和 200 个外爪）进行了计算机断层扫描（CT）检查，以研究溃疡恶化的病因理论，即远端趾骨内屈突的外生骨赘是溃疡恶化的一个诱发因素。通过 3D CT 可以观察到牛后肢爪子屈突的各种形态变化，这些爪子的几何形状表明了骨骼发育的生长模式，与假设的日常负荷模式有关。这种生长最初发生在远端趾骨的背侧尾端，然后向轴向方向水平推进。在远端趾骨的掌侧，外爪的向下（垂直）骨发育长度为 2.73±1.32mm，显著大于内爪（2.38±0.96mm）。外爪和内爪的向下（垂直）骨发育与皮下组织和真皮层厚度的比值（VerBD 比值）无差异（分别为 36.7%和 38.3%）。外爪和内爪的水平骨发育与屈突轴向-背侧线的比值（HorBD 比值）约为 60%。这些关于远端趾骨内水平和垂直骨发育的定量测量值与年龄和 VerBD 比值呈正相关（内爪和外爪分别为 r=0.53 和 r=0.36）。外爪爪宽与垂直骨发育长度（r=0.43）、HorBD 比值（r=0.51）和 VerBD 比值（r=0.42）之间的相关性表明，内爪和外爪之间的相对大小差异增强了外爪的骨发育。VerBD 和 HorBD 比值之间的相关系数（内爪和外爪分别为 r=0.52 和 r=0.63）表明，屈突内的水平和垂直骨发育是一个同步的过程。这种与年龄相关的屈突内骨发育进展与暴露于多个恶化因素和蹄叶炎过程有关。
