This is the 10923rd most frequent Korean word.
근육을
"근육을" means "muscles" (object form).
In this context, '근육을' refers to the muscles being the object of examination or observation by the doctor.
의사는 환자의 근육을 확인했습니다.
The doctor examined the patient's muscles.
The term '근육을' is used to refer to muscles in the context of physical development or enhancement.
운동을 해서 근육을 키우고 있습니다.
I am working out to build muscles.
Here, '근육을' is used to describe putting muscles into action for a specific task.