Hines A E, Birn H, Teglbjaerg P S, Sinkjaer T
Department of Medical Informatics and Image Analysis, Aalborg University, Denmark.
Anat Rec. 1996 Dec;246(4):573-8. doi: 10.1002/(SICI)1097-0185(199612)246:4<573::AID-AR18>3.0.CO;2-L.
We examined the fiber type composition of the articular branches of the tibial nerve in human cadavers. Our primary motivation was to assess the suitability of these nerve branches for making neural recordings by using an interface, such as a nerve cuff electrode or a microelectrode array. Articular branches of the tibial nerve innervate primarily the posterior joint capsule of the knee (Gardner, 1948. Anat. Rec, 101:109-130); the main branch corresponds anatomically to the posterior articular nerve (PAN), which has been studied extensively in animals such as the cat.
By using light microscopy, we counted the numbers of myelinated fibers in articular branches of the tibial nerve removed from eight cadavers. Unmyelinated fibers were counted in the same specimens by using electron microscopy, and the percentage of unmyelinated fibers was calculated.
We found on average 2,280 myelinated fibers in the main articular branch and 279 fibers in individual capsular ramifications. Myelinated fiber diameter histograms showed either bimodal (peaks at 3-4 and 9 microns) or unimodal (peak at 3-4 microns) distributions, depending on the specimen. These histograms were similar in appearance for both the individual capsular ramifications and the main articular branch of the tibial nerve. Numbers of unmyelinated fibers ranged from 4,176 to 5,200 in the main tibial nerve branch (average percentage of unmyelinated fibers = 69.6%) and from 750 to 2,250 in the individual capsular ramifications (average percentage of unmyelinated fibers = 78.5%).
The percentage of unmyelinated fibers is comparable to that found in articular nerves in other species. We discovered that the main articular branch of the tibial nerve contains a branch projecting distal to the knee joint capsule; therefore, the best location for placement of a neural recording interface to record from capsular afferents appears to be the well-defined ramifications of the articular branch that penetrate the joint capsule. Branches that contain only these ramifications are 0.5-1.0 mm in diameter and, on average, have 658 myelinated axons, which should be a sufficient number from which to record.
我们研究了人类尸体中胫神经关节支的纤维类型组成。我们的主要目的是评估这些神经支对于使用神经袖套电极或微电极阵列等接口进行神经记录的适用性。胫神经的关节支主要支配膝关节的后关节囊（加德纳，1948年。《解剖学记录》，101:109 - 130）；主要分支在解剖学上对应于后关节神经（PAN），该神经在猫等动物中已得到广泛研究。
通过光学显微镜，我们对从八具尸体上取下的胫神经关节支中的有髓纤维数量进行了计数。使用电子显微镜对相同标本中的无髓纤维进行计数，并计算无髓纤维的百分比。
我们发现，主要关节支平均有2280条有髓纤维，单个关节囊分支有279条纤维。有髓纤维直径直方图显示出双峰分布（峰值在3 - 4微米和9微米处）或单峰分布（峰值在3 - 4微米处），具体取决于标本。对于单个关节囊分支和胫神经的主要关节支，这些直方图在外观上相似。在胫神经主要分支中，无髓纤维数量在4176至5200条之间（无髓纤维平均百分比 = 69.6%），在单个关节囊分支中为750至2250条（无髓纤维平均百分比 = 78.5%）。
无髓纤维的百分比与其他物种关节神经中的情况相当。我们发现胫神经的主要关节支包含一条向膝关节囊远端延伸的分支；因此，用于记录关节传入神经信号的神经记录接口的最佳放置位置似乎是穿透关节囊的关节支的明确分支。仅包含这些分支的神经直径为0.5 - 1.0毫米，平均有658条有髓轴突，这应该是足以进行记录的数量。
