Purpose

To investigate the innervation pattern of the sacroiliac region, especially with regard to the sacroiliac joint (SIJ). Dorsal SIJ innervation was analyzed and described. Our main hypothesis was that nerves reach the SIJ dorsally, passing ligamental compartments, as this would explain dorsal SIJ pain.

Methods

To examine sacroiliac innervation, we followed the nerves in over 50 specimens over several years. Plastinated slices were evaluated, nerves in the region were stained histologically, and the data were summarized as 3D models.

Results

The Rami communicans and posterior branches of the spinal nerves and their branches that form a dorsal sacral plexus and communicating branches, together with corresponding vessels, were observed to form neurovascular bundles embedded by tiny fatty connectives in gaps and tunnels. Branches of L5-S1 pass the inner sacroiliac ligaments (the interosseous sacroiliac ligament and axial interosseous ligament). The outer sacroiliac ligaments (posterior sacroiliac ligaments, long posterior sacroiliac ligament, sacrotuberal ligament, thoracolumbar fascia) are passed by the S1-S4 branches. However, although the paths of these nerves are in the direction of the SIJ, they do not reach it. It is possible that impingement of the neurovascular bundles may result in pain. Moreover, the gaps and tunnels connect to the open dorsal SIJ.

Conclusion

Our findings suggest that Bogduk’s term “sacroiliac pain” correlates to “sacroiliac innervation”, which consists of “inner-” and “outer sacroiliac ligament innervation”, and to ventral “SIJ pain”. The watery gaps and tunnels observed could play a significant role in innervation and thus in the origins of SIJ pain.

Level of evidence

Individual cross-sectional studies with consistently applied reference standard and blinding.

中文翻译：

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骶髂神经支配

目的

研究骶髂区域的神经支配模式，尤其是关于骶髂关节 (SIJ) 的神经支配模式。分析和描述了背侧 SIJ 神经支配。我们的主要假设是神经到达 SIJ 背侧，穿过韧带间隙，因为这可以解释背侧 SIJ 疼痛。

方法

为了检查骶髂神经支配，我们在几年内跟踪了 50 多个标本中的神经。对塑化切片进行了评估，对该区域的神经进行了组织学染色，并将数据汇总为 3D 模型。

结果

观察到脊神经的交际支和后支及其形成骶背丛和交通支的分支，以及相应的血管形成由微小脂肪结缔组织嵌入间隙和隧道中的神经血管束。L5-S1的分支穿过内骶髂韧带（骨间骶髂韧带和轴向骨间韧带）。骶髂外韧带（骶髂后韧带、骶髂后长韧带、骶结节韧带、胸腰筋膜）由S1-S4分支穿过。然而，尽管这些神经的路径指向 SIJ 的方向，但它们并没有到达它。神经血管束的撞击可能会导致疼痛。此外，间隙和隧道连接到开放的背侧 SIJ。

结论

我们的研究结果表明，Bogduk 的术语“骶髂疼痛”与“骶髂神经支配”相关，后者包括“内骶髂韧带”和“外骶髂韧带神经支配”，以及腹侧“SIJ 疼痛”。观察到的水样间隙和隧道可能在神经支配中发挥重要作用，从而在 SIJ 疼痛的起源中发挥重要作用。

证据等级

具有一致应用的参考标准和盲法的个体横断面研究。