OBJECTIVE To describe the imaging features of bipartite medial cuneiform and to determine the prevalence of this rare anatomical variant in a large group of patients that were evaluated by magnetic resonance imaging (MRI) of the foot. MATERIALS AND METHOD Seven hundred and fifty-one patients that underwent MRI of the foot from May 2016 to December 2018 were included in the study (mean age 49 years; 540 females; 211 males). All MRIs were retrospectively analyzed to identify bipartite medial cuneiform. For patients with bipartite medial cuneiform, we analyzed partial and complete bipartition, the type of articulation (synchondrosis, syndesmosis, or a combination of these two), and stress changes related to abnormal motion (i.e., subchondral cysts and sclerosis). Bone marrow edema-like signal, diastasis in the cleavage plane, concomitant fractures, and the presence of the E-sign were also evaluated. RESULTS Nine feet from six patients presented bipartite medial cuneiform on the MRI. Six and three feet exhibited complete and partial bipartition. All patients were referred for MRI because of midfoot pain, of which two had history of trauma prior to imaging. Stress changes related to abnormal motion were observed in three feet (34%), all with complete bipartition. Bone marrow edema-like signal was recorded in five feet (55%) and diastasis in one foot (11%). No fractures were present in the bipartite medial cuneiform. All patients had E-signs. CONCLUSION Bipartite medial cuneiform is a rare anatomical variant occurring in 0.79% of patients who underwent foot MRI in this study. It is important to be aware of this variant as it is a cause of midfoot pain. Being familiar with the E-sign helps identify and differentiate it from a fracture.

中文翻译：

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二部内侧楔形文字：磁共振成像发现和这种罕见解剖变异的患病率。

目的描述二足内侧楔形文字的影像学特征，并确定在脚部磁共振成像（MRI）评估的一大批患者中这种罕见的解剖变异的患病率。材料与方法研究纳入了2016年5月至2018年12月接受脚MRI检查的511例患者（平均年龄49岁；女性540岁；男性211岁）。回顾性分析所有MRI，以识别二部内侧楔形文字。对于患有双侧内侧楔形文字的患者，我们分析了部分和完全的双分割，关节的类型（关节软骨病，下颌联合症或这两者的组合）以及与异常运动有关的压力变化（即软骨下囊肿和硬化）。骨髓水肿样信号，乳沟平面内转移，伴有骨折，并且评估了电子签名的存在。结果六例患者的九只脚在MRI上呈双半楔形。六英尺和三英尺显示出完全的和部分的分隔。由于脚中部疼痛，所有患者均接受了MRI检查，其中两名患者在成像前有外伤史。在三脚（34％）中观察到与异常运动有关的压力变化，所有运动都完全分开。在五英尺（55％）处记录到了类似骨髓水肿的信号，而在一只脚（11％）处则出现了消化不良。二头内侧楔形骨中没有骨折。所有患者均具有电子体征。结论在本研究中，二足内侧楔形文字是一种罕见的解剖变异，发生在0.79％接受足部MRI的患者中。重要的是要意识到这种变体，因为它是导致脚中部疼痛的原因。