Organization of peripheral nerves in skin, musculoskeletal system and viscera.
ABSTRACT Skin, musculoskeletal system and all organs of the body are supplied by nerve fibers of the somatic and autonomic nervous system, each of the systems with its specific nerve fiber types, fiber composition, fiber density and targets. Experimental data support the hypothesis that tumor tissue might interact with nerve fibers. The peripheral nervous system possesses an extraordinary cellular equipment to protect the axons against pathological stimuli. Only restricted areas lacking a cellular barrier are weak points within the nervous network. Therefore, this article focuses on the functional morphology of the peripheral nervous system and its regional differences.
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ABSTRACT: This study of spontaneous abortions and fetal deaths in utero used immunostains to evaluate the structure of developing cutaneous nerves. Melan-A immunostains were also used to screen 25 cases of grossly normal fetal skin for occult fetal nevi. Discrete portions of epidermis were generally supplied by branches emanating from regularly spaced deep cutaneous nerves, producing a wedge shape, interpreted as neurocutaneous units (NCU). Deeper nerves embraced broader portions of epidermis. Some nerves ran parallel to epidermis, especially near the superficial vascular plexus at the junction of superficial and deep dermis. Nerve sheath stem cells in each NCU may supply the melanocytes needed by the corresponding portion of epidermis. Transformed nerve sheath stem cells may lead to formation of occult prenatal nevi, whose histology and histogenesis may best be understood in terms of NCUs. In particular, the size and shape of a nevus may be largely determined by its NCU of origin. Six fetal nevi were detected, and 3 occult lumbosacral Mongolian spots; all in deep dermis, no later than the middle of the second trimester, mainly with a pattern of singly dispersed deep dermal melanocytes. These findings suggest that congenital (prenatal) nevi begin as intradermal nevi. In addition to explaining congenital nevi, these findings have implications for the histogenesis of acquired (postnatal) nevi and dysplastic nevi.The American Journal of dermatopathology 12/2011; 34(1):60-81. · 1.30 Impact Factor