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

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

There is a serious opposition between them.

He injured his little finger.

He injured his little finger.

I strained a muscle at the gym yesterday.

He is doing a special exercise to strengthen his extensor digiti minimi.

He is doing special exercises to strengthen the opponens digiti minimi muscle of his foot.

My opponens pollicis muscle hurts.

He is doing a special exercise to strengthen his flexor digiti minimi brevis.