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

The flexor digitorum brevis is a part of the muscles of the foot, playing a role in bending the toes.

He stretches his flexors every day.

My flexor pollicis brevis hurts.

He is doing special exercises to strengthen his flexor hallucis brevis.

He injured his little finger.

He injured his little finger.

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

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

I strained a muscle at the gym yesterday.