Vandenabeele F, Creemers J, Lambrichts I, Lippens P, Jans M
Department of Basic Medical Sciences, Limburgs Universitair Centrum, Diepenbeek, Belgium.
J Anat. 1997 Nov;191 ( Pt 4)(Pt 4):571-83. doi: 10.1046/j.1469-7580.1997.19140571.x.
The innervation of the human lumbar facet joint capsule was studied by light and electron microscopy. Small numbers of encapsulated corpuscular endings were identified in the dense fibrous layer. Clusters of 2 types of endings were found: small cylindrical corpuscles (type 1) and large fusiform corpuscles (type 2). The corpuscles were classified structurally as Ruffini-type endings. The 1st type was predominant and characterised by a compartmentalised receptor complex, a thin perineurial capsule and a narrow subcapsular space. The 2nd type was characterised by a thicker perineurial capsule, a 'spindle-like' receptive complex, and an extensive subcapsular space with capillaries and concentrically oriented fibroblast-like cells. Both types of endings were innervated mainly by thinly myelinated group III (A delta) and unmyelinated group IV (C) nerve fibres that branched and terminated in the receptor complex. Their sensory endings were intimately related to the collagen fibre bundles as multiple enlarged axonal segments ('beads') with ultrastructural features which were characteristic of receptive sites: an accumulation of mitochondria and vesicles, and 'bare' areas of axolemma lacking a Schwann cell investment but covered by a thin basal lamina. Some beads in the 2nd type of ending contained granular vesicles, 30-60 mm in diameter, resembling sympathetic nerve endings. Small diameter collagen fibrils situated within multilayered basal laminae were found among the multiple receptive sites in the receptive complex in both types of ending. Their possible functional significance in mechanoreception is discussed. Particular attention has been given to their apparent variable orientation to the mechanoreceptive site.
通过光学显微镜和电子显微镜对人腰椎小关节囊的神经支配进行了研究。在致密纤维层中发现了少量被囊小体终末。发现了两种类型终末的簇：小圆柱状小体（1型）和大梭形小体（2型）。这些小体在结构上被归类为鲁菲尼氏型终末。1型占主导，其特征是有分隔的受体复合体、薄的神经束膜被囊和狭窄的被囊下间隙。2型的特征是神经束膜被囊较厚、“纺锤状”感受复合体以及有毛细血管和同心排列的成纤维细胞样细胞的广泛被囊下间隙。两种类型的终末主要由薄髓鞘的III组（Aδ）和无髓鞘的IV组（C）神经纤维支配，这些神经纤维在受体复合体内分支并终止。它们的感觉终末与胶原纤维束密切相关，表现为多个增大的轴突节段（“珠子”），具有感受位点的超微结构特征：线粒体和小泡的聚集，以及轴膜的“裸露”区域，该区域缺乏施万细胞覆盖，但被薄的基膜覆盖。2型终末中的一些珠子含有直径为30 - 60μm的颗粒小泡，类似于交感神经终末。在两种类型终末的感受复合体内的多个感受位点中，发现了位于多层基膜内的小直径胶原纤维。讨论了它们在机械感受中的可能功能意义。特别关注了它们相对于机械感受位点明显可变的方向。
