腰こしを抜ぬかす

expression, godan verb (-su)

dislocate one's back; throw out one's back

Literal physical meaning: to injure the lower back so severely that one cannot stand. Less common than the figurative sense.

See also: 腰抜かす

• 重おもい荷に物もつを持もち上あげようとして腰こしを抜ぬかした。

  I threw out my back trying to lift a heavy load.

expression, godan verb (-su)

be unable to stand from fear or surprise; be paralyzed with shock

Figurative use: to be so shocked, frightened, or surprised that one's legs give out and one cannot stand up. This is the more common meaning.

• 突とつ然ぜんの大おおきな音おとに腰こしを抜ぬかした。

  I was so startled by the sudden loud noise that I couldn't stand up.

• 彼かれはその知しらせを聞きいて腰こしを抜ぬかさんばかりに驚おどろいた。

  He was so shocked at the news that he nearly collapsed.