My opponens pollicis muscle hurts.

My head hurts.

She opened the book with her thumb.

There is a serious opposition between them.

He and she were standing against each other due to a disagreement.

He grimaced and said, 'It hurts.'

He underwent surgery due to an injury to the opponens digiti minimi muscle.

I strained a muscle at the gym yesterday.

My flexor pollicis brevis hurts.

He is doing special exercises to strengthen his flexor pollicis longus.