knuckle joint

例句：

1. 1. The doctor examined the patient's knuckle joint and found no signs of infection.
   医生检查了患者的关节连接处，没有发现感染的迹象。
2. 2. The dancer's knuckle joint is so flexible that she can perform acrobatics with ease.
   舞者的关节连接处如此灵活，她可以轻松地执行杂技。
3. 3.The scientist studied the structure of the knuckle joint in order to understand its function.
   科学家研究了关节的结构，以了解其功能。