YOU SAID:

I threw an onion at my horses metacarpal

INTO JAPANESE

私は馬の中手骨にタマネギを投げました

BACK INTO ENGLISH

I threw an onion into the metacarpal bone of a horse

INTO JAPANESE

タマネギを馬の中手骨に投げた

BACK INTO ENGLISH

Throw the onion into the metacarpal bone of the horse

INTO JAPANESE

タマネギを馬の中手骨に投げ入れる

BACK INTO ENGLISH

Throw the onion into the carpal bone of the horse

INTO JAPANESE

タマネギを馬の手根骨に投げ込む

BACK INTO ENGLISH

Throw the onion into the carpal bone of the horse