She uses a diminutive in her name to express cuteness.

He decided to lose weight for his health.

He exercises every day to become thin.

Her slender fingers are suitable for playing the piano.

纖 is a kanji that you don't see very often.

My opponens pollicis muscle hurts.

He underwent surgery due to an injury to his extensor digitorum communis.

He is doing special exercises to strengthen his flexor digitorum superficialis.

He is doing special exercises to strengthen his flexor digitorum profundus.

He is doing a special exercise to strengthen his extensor indicis.