肱

曲肱而枕

qū gōng ér zhěn

lit. to use one's bent arm as a pillow (idiom)

股肱

gǔ gōng

trusted aide

肱三头肌

gōng sān tóu jī

triceps brachii (back of the upper arm)

肱二头肌

gōng èr tóu jī

bicipital muscle

肱骨

gōng gǔ

humerus