Same character 拉 as the everyday 拉 (to pull), but rising second tone instead of flat first. Context picks the reading: when the object is a cut, gash, or opening (口子, 伤口), say lá; when you are pulling, dragging or playing an instrument, say lā.
memory
Picture the rising tone as the rising blade: lā (flat) drags something across, lá (rising) lifts edge into skin and slices. Same hand, sharper motion.
Left-side hand radical, the side form of 手. Anchors 拉 in the manual-action family - pulling, dragging, tugging are core hand activities. Same radical drives 推 (push), 抓 (grab), 扔 (throw), 打 (hit). Provides essentially all the meaning while 立 just supplies sound.
Right side 立 supplies the sound (lì → lā, just a tone shift). 立 itself pictures a person planted firmly on the ground. Faint semantic flavour: pulling something requires bracing yourself - 'standing your ground' to drag. Same phonetic in 粒 (grain) and 位 (position).
