Sentence:  The carpal bones are usually described as being capable of being luxated from the lower end of the radius forwards or backwards, inwards or outwards. The case backwards, which has been stated to be the most frequent, is facilitated by the direction of the convex articular surfaces of the scaphoid, <WSD>lunar</WSD>, and cuneiform bones, which slope more backwards than forwards. 
Meaning of the word marked with <WSD> tags:  The middle bone of the proximal series of the carpus in the wrist, which is shaped like a half-moon.