lunar

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, lunar, and cuneiform bones, which slope more backwards than forwards.]

[Y]oung beginners cannot be too often cautioned that a single lunar is of little or no value until the observer knows the usual difference between his lunars taken on opposite sides of the moon; and these should be taken with the same instrument, using the same screens and telescope, for he must remember that they may be expected to differ. My star lunars differ from three to four minutes, or say fifty miles of longitude; my sun lunars from one to two minutes, or say twenty minutes of longitude.