expression, godan verb (-ru)
undergo surgery; be operated on
Literal medical sense: a scalpel is used, i.e., surgery is performed. The subject is the patient or body part.
See also: メスを入れる (メスをいれる)
彼は事故で大けがをして、すぐにメスが入った。
He was seriously injured in the accident and underwent surgery immediately.
expression, godan verb (-ru)
be investigated; be scrutinized; drastic measures are taken
Figurative extension: a problem or organization is subjected to thorough investigation, reform, or drastic action, as if a scalpel is applied.
See also: メスを入れる (メスをいれる)
不正会計の問題に、ついに監査のメスが入った。
The accounting fraud finally came under the scrutiny of an audit.
長年放置されてきた組織に、改革のメスが入った。
Drastic reform measures were finally taken for the long-neglected organization.