The collagenic structure of human digital skin seen by scanning electron microscopy after Ohtani maceration technique

We performed a morphological scanning electron microscope (SEM) study to describe the fine structure and disposition of collagenous tissue in the human toe. After therapeutic amputation of a human right leg, we applied the Othani maceration technique to the skin of three toes surgically explanted from the foot. We distinguished eight cutaneous regions and focused on some specialized collagenous structures differing in the thickness of the skin. The eight areas investigated were: the dorsal skin, the eponychium, the perionychium, the hyponychium, the region under the visible nail, the nail root, the plantar skin and finally the toe tip. Each of these areas is characterized by a distinctive collagenous surface disposition, with some peculiar features mostly related to dermal papillae. At high magnification, we observed the spatial arrangement of the collagen fibers constituting the top of the dermal papillae that represents the attachment site of the proliferative basal layer of the epidermis. We also noted an impressive density of collagen fibers throughout the thickness of the dermal layer, organized in specialized structures and constituting the skeleton of dermal thermoreceptorial corpuscles or sweat glands. A combination of SEM and Ohtani technique disclosed the three-dimensional architecture of the collagenous matrix of tarsal skin under physiologic conditions, giving a detailed description of the most reactive tissue during pathologic processes.