及膝 + Noun / 膝 + 盖
The noun 膝 (xī) means knee, referring to the joint in the middle of the leg. It commonly appears in compounds such as 膝盖 (kneecap) and in descriptive phrases like 及膝 (reaching the knee). It is used in both everyday and medical contexts.
他跑步的时候伤了膝盖。
Tā pǎobù de shíhòu shāng le xīgài.
He injured his knee while running.
这条裙子刚好到膝盖的位置。
Zhè tiáo qúnzi gānghǎo dào xīgài de wèizhì.
This skirt reaches right to the knee.
奶奶最近膝盖疼,走路不太方便。
Nǎinai zuìjìn xīgài téng, zǒulù bú tài fāngbiàn.
Grandma's knees have been hurting recently, so it's not very easy for her to walk.