[名词解释] 环后隙

Waldeyer淋巴环 女，9岁，颈部疼痛、活动受限2个月，MRI检查如图，最可能的诊断为() ["A．室管膜瘤","B．星形细胞瘤","C．神经鞘瘤","D．髓内囊肿","E．脊膜瘤"] pharyngealbursa 女，3岁，头痛、呕吐1周，结合MRI图像，最可能的诊断是() ["A．脑膜炎","B．硬膜下出血","C．脑转移瘤","D．脑梗死","E．脑脓肿"] 腺样体 环后隙