筋肉

1. Origins, structure, and basic meaning

• Structure: 筋肉 is read as きんにく and is a noun for muscle tissue or the muscles of a particular body part.
• Basic usage: Specify the body area with 足の筋肉 and the subject studied with 腕の筋肉の動き.

2. Common pitfalls and similar expressions

• Body area and condition
  • 足の筋肉が張る describes the leg muscles feeling tight after exercise.
• Muscle and movement
  • The model is used to study 筋肉の動き, the way the arm muscles move, rather than the arm as an undivided whole.