示指；ひとさしゆび（第二指） - Index; digitus secundus [II]
The index finger, (also referred to as forefinger, pointer finger, trigger finger, digitus secundus, digitus II, and many other terms), is the first finger and the second digit of a human hand.
It is located between the first and third digits, between the thumb and the middle finger. It is usually the most dextrous and sensitive finger of the hand, though not the longest – it is shorter than the middle finger, and may be shorter or longer than the ring finger – see digit ratio.
一般解剖学 > Regions of human body > 上肢の部位 > 手部 > 指 > 示指；ひとさしゆび（第二指）