Bragulla Hermann
Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Freie Universität Berlin, 14195 Berlin, Germany.
J Morphol. 2003 Nov;258(2):207-24. doi: 10.1002/jmor.10142.
Fetal development of the unique papillary body and its localized peculiarities in the equine hoof are described based on the study of 51 fetuses, nine newborn foals, and five adult horses. The shape and dimensions of the dermal papillae and lamellae have a formative influence on the structure and physical quality of the corneous hoof capsule with its horn tubules and lamellae. The size and arrangement of these horn structures determine the mechanical quality of hoof horn. Proper horn quality is a prerequisite for the various functions of the hoof capsule, such as protecting the living dermis supporting the hoof capsule, shock absorption, and formation of the suspensory apparatus of the distal phalanx. Development of the segment-specific papillary body is initiated by the increasing mitotic activity of the epidermal cells invaginating the dermal surface, thus forming dermal microridges. These microridges are transformed into single dermal papillae, which are arranged in rows, or enlarged to become primary and secondary dermal lamellae. The formation of a segment-specific papillary body enables the increasing keratinization ratio in the hoof epidermis and the formation of the characteristic tubular and lamellar horn responsible for the special mechanical properties of hoof horn.
基于对51例胎儿、9匹新生马驹和5匹成年马的研究，描述了马属动物蹄中独特乳头体的胎儿发育及其局部特征。真皮乳头和板层的形状及尺寸对具有角质蹄匣及其角质小管和板层的结构和物理性质具有形成性影响。这些角质结构的大小和排列决定了蹄角质的机械性能。适当的角质质量是蹄匣各种功能的先决条件，例如保护支撑蹄匣的活真皮、减震以及形成远节指骨的悬韧带装置。特定节段乳头体的发育是由侵入真皮表面的表皮细胞有丝分裂活性增加引发的，从而形成真皮微嵴。这些微嵴转化为单行排列的单个真皮乳头，或扩大形成初级和次级真皮板层。特定节段乳头体的形成使得蹄表皮中的角质化率增加，并形成负责蹄角质特殊机械性能的特征性管状和板层角质。
