Coitus interruptus is one method of contraception, but it is not completely reliable.

This book explains in detail about the use of foreign words.

This sentence contains kanji not approved for regular use.

This sentence contains non-Jōyō kanji.

There are many introduced species of plants living in this park.

He started exercises to strengthen his abductors.

He is doing special exercises to strengthen his supinator.

He underwent surgery on his extraocular muscle.

He is doing special exercises to strengthen his external obturator muscle.

The external intercostal muscle plays an important role in respiration.