Top: plant 艹, below: extensive 溥 (The water 氵 announces 尃 that it is extensively widespread) Here cf. shoulder 膊: The body part 月/肉, that somehow looks like the upper body 甫 with the 'skillful hand' 寸 is the shoulder.
Mnemonic
If you only get plants and water as provisions, the schoulders will be: meager and weak.
Image of a hand 一 forearm 丨 and pulse 丶. As a body part this is the forearm 肘. It was originally also the distance of one inch (Length: 1 ts'wun = 3.72 cm) from the hand's palm to the pulse. This also stood for a small amount. In the mnemonic, it is used as "skillful hand".
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