BACKGROUND: The clinical importance of Guyon's canal is emphasized due to the various branching patterns of the ulnar nerve. So far, the arborization pattern of the ulnar nerve in Guyon's canal has been investigated mostly by cadaveric studies. PURPOSE: To demonstrate anatomic variations of the ulnar nerve in Guyon's canal in vivo by using high definition ultrasound (US) and 3 T magnetic resonance imaging (MRI). MATERIAL AND METHODS: US imaging and 3 T MRI with an 8-channel coil was applied to 30 hands of 15 volunteers. The main trunk and the branched superficial and deep ulnar nerves, including neural bifurcation or trifurcation, were recognized on US and confirmed by 3 T MR images. The ulnar artery and vein and its branches were traced on color Doppler US and also visualized by MRI. The branching pattern of the ulnar nerve was determined from the inlet to the outlet of Guyon's canal. RESULTS: Of 30 hands, 21 (70%) revealed bifurcation and 9 (30%) had trifurcation branching pattern of the ulnar nerve. In 16 hands (54%), imaging demonstrated that a single nerve entered the canal and divided into two trunks, one superficial and one deep, then exited the canal. The bifurcation occurred predominantly just after entering the canal inlet. The typical trifurcation pattern indicated that a single trunk entered the canal and divided into two, then one of the two bifurcated, producing a trifurcated pattern with two superficial and one deep bundle. Of 15 participants, symmetrical branching of bilateral hands was identified in 4 cases (27%), whereas 11 (73%) had asymmetrical branching. CONCLUSION: US and 3 T MRI readily delineated the branching pattern of the ulnar nerve in Guyon's canal in vivo. Morphological understanding about this neural branching can be informative in presurgical planning and also in diagnosis.
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机译：背景：由于尺神经的各种分支方式，强调了古永管的临床重要性。到目前为止，绝大部分Guyon运河中尺神经的乔化模式已通过尸体研究进行了调查。目的：通过使用高清晰度超声（US）和3T磁共振成像（MRI）来证明盖永管内尺神经的解剖学变化。材料与方法：将US成像和带有8通道线圈的3 T MRI应用于15名志愿者的30只手。在US上可以识别主干以及分支的浅和深尺神经，包括神经分叉或三叉神经，并通过3 T MR图像进行确认。在彩色多普勒超声上追踪尺动脉和静脉及其分支，并通过MRI可视化。尺神经的分支模式是从古永管的入口到出口确定的。结果：在30只手中，有21只（70％）表现出分叉，而9只（30％）有尺神经的三叉分支模式。影像学检查显示，在16只手中（54％）中，一条神经进入了根管，并分成两条主干，一条浅表和一根深，然后退出了根管。分叉主要发生在进入运河入口之后。典型的分叉样式表明，单个干渠进入运河并分成两部分，然后是两个分叉的一个，从而产生了带有两个浅表层和一个深束的分叉样式。在15名参与者中，有4例（27％）鉴定出双侧手对称分支，而11例（73％）有不对称分支。结论：US和3T MRI可以很容易地勾勒出古永管内尺神经的分支形态。对这种神经分支的形态学理解可以在术前计划和诊断中提供信息。
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