Positional plagiocephaly is the most common cause of cranial asymmetry. Deformational brachycephaly denotes a head shape characterized by occipital flattening and increased bilateral width, which can also be caused by external deformation of the moldable infant cranium in positional bilateral posterior plagiocephaly. There are reports of craniosynostosis associated with Chiari I malformation (CIM), possibly caused by decreased posterior fossa volume and related to increased intracranial pressure. To the best of our knowledge, this is only the second case report demonstrating acquired CIM in a child with positional brachycephaly. Of note, the fact that the CIM resolved after helmet therapy could support the hypothesis that CIM is associated with decreased volume of the posterior fossa. However, these two conditions may be independent of one another. More research is needed to identify an association between the two conditions.

位置性斜头畸形是颅骨不对称的最常见原因。变形性短头畸形是指头部形状的特征是枕骨变平和双侧宽度增加，这也可能是由于位置性双侧后斜头畸形中可塑婴儿颅骨的外部变形引起的。有报道称颅缝早闭与 Chiari I 畸形 (CIM) 相关，这可能是由后颅窝容积减少和颅内压升高引起的。据我们所知，这只是第二个病例报告，显示位置性短头畸形儿童获得性 CIM。值得注意的是，头盔治疗后 CIM 消退的事实可以支持 CIM 与后颅窝体积减少有关的假设。然而，这两个条件可以彼此独立。