The Royal Veterinary College, UK.
Equine Vet J. 2010 Nov;42(8):726-31. doi: 10.1111/j.2042-3306.2010.00114.x.
REASONS FOR STUDY: Detailed anatomy of the equine cervical articular process joints (APJs) has received little attention in the literature and yet disorders of this joint have been linked to spinal cord compression resulting in severe clinical signs such as ataxia and weakness. This study aimed to describe the 3D anatomy of the APJ in relation to the spinal cord in the horse.
Artificial distension of the APJ causes the joint pouches to extend into the vertebral canal, with the potential for APJ effusion to cause spinal cord compressive disease.
Six cadaveric necks (C1-C7) of clinically normal horses were used in this study. Computed tomography scans of the cervical APJ were acquired after injection of a negative contrast agent to maximal distension. The resulting images were semi-automatically segmented using greyscale thresholding and reconstructed in 3D by polygonal surface meshing. The 3D reconstructions were used to assess the topographic anatomy of the APJ in relation to the spinal cord and to measure joint volume at each cervical vertebra in relation to vertebrae size.
Joint volume varied significantly between joint location (P<0.0001) and was positively correlated to the vertebral site (from cranial to caudal) (r = 0.781, P<0.0001). After distension, the medial outpouch of the APJ extended towards the vertebral canal from a dorsolateral location but in none of the 6 horses was there apparent compression of the dura mater surrounding the spinal cord. There was no significant difference in the extent of medial outpouch at any vertebral level (P = 0.104). Flexion of the neck resulted in minor changes to the shape of the APJ but did not result in the medial outpouch encroaching any closer to the spinal cord.
From this study, it appears that in the absence of any other soft tissue or bony changes an effusion of the APJ is unlikely to cause spinal cord compression. However, given that the APJ and spinal cord are in close approximation, in the presence of other anatomical changes, an effusion may have the potential to cause compression.
This study confirms that the APJ extend into the dorsolateral aspect of the vertebral canal in a ventromedial direction, suggesting that oblique myelographic views are recommended for the diagnosis of spinal cord compression when pathology of the APJ is suspected.
研究原因：马颈椎关节突关节（APJ）的详细解剖结构在文献中很少受到关注，但该关节的疾病与脊髓受压有关，导致严重的临床症状，如共济失调和虚弱。本研究旨在描述 APJ 与马脊髓的 3D 解剖关系。
APJ 的人工扩张导致关节囊延伸到椎管内，APJ 渗出物有可能导致脊髓压迫性疾病。
本研究使用了 6 具临床正常马的颈椎（C1-C7）进行研究。在最大扩张后向 APJ 注射负对比剂后，获得颈椎 APJ 的计算机断层扫描。使用灰度阈值半自动分割和多边形表面网格重建 3D 图像。使用 3D 重建评估 APJ 与脊髓的局部解剖关系，并测量每个颈椎关节的关节体积与椎体大小的关系。
关节体积在关节位置之间存在显著差异（P<0.0001），与椎体位置（从颅侧到尾侧）呈正相关（r = 0.781，P<0.0001）。扩张后，APJ 的内侧外突从背外侧向椎管延伸，但在 6 匹马中均未见明显压迫脊髓周围硬脑膜。在任何椎体水平，内侧外突的程度均无显著差异（P = 0.104）。颈部弯曲使 APJ 的形状发生轻微变化，但不会导致内侧外突更靠近脊髓。
从本研究来看，在没有任何其他软组织或骨改变的情况下，APJ 渗出物不太可能导致脊髓压迫。然而，由于 APJ 和脊髓非常接近，在存在其他解剖变化的情况下，渗出物有可能导致压迫。
本研究证实 APJ 向腹侧和内侧方向延伸到椎管的背外侧，这表明当怀疑 APJ 病理学时，建议采用斜位脊髓造影术诊断脊髓压迫。
