[名词解释] 马牙或板牙(fronttooth)

在柯氏位上，正常上颌窦的形态为() ["A．正方形","B．倒三角形","C．梯形","D．正三角形","E．长方形"] 安装起搏器后出现下列哪组症状需马上到医院就诊() ["A．睡眠不佳","B．感觉无力","C．胸痛、呃逆、发热、呼吸困难","D．小便次数稍增加","E．自感记忆减退"] 晚期代谢性酸中毒 早产儿视网膜病 中性温度 马牙或板牙(fronttooth)