How can I distinguish between a torn ligament and a bad ankle sprain?

Can be the same... HI! An ankle sprain can be a varying degree of tendon or ligament damage. Usually, if a ligament is badly injured / damaged there will / can be excessive ' loosenes' of the affected joint or exceesive motion between the two bones the ligament joins. This should be easily determined in most cases by a competent exam including various stress and range of motion testing ie: ankle anterior draw test.

Related Questions

Torn ligament plus sprained ankle, how long will it take to recover?

Depends on severety. It is very dependent on your rehabilitation/ physical therapy, diet, age, physical shape, etc. On average, it may take 2-3 month for most of recovery to complete. Read more...
Sprain. As stated , it can take as long to heal from a sprain as a fracture. See your treating physician for any and all questions. Read more...

Sprained my ankle 2 weeks ago. Pain is right behind ankle bone. Dr thinks it's a torn ligament but didn't ask for mri. Is that normal /should I get one?

Probably. Best imaging test to diagnose injured tendons and ligaments is mri. Your doctor may think that knowing for sure what the injury is will not change his treatment and therefore does not want to do the study. Need to ask him or her why not. Read more...

I sprained my ankle 3 months ago, still swollen and it is tender around my talar dome/fibula. Is it a possible ligament tear?

Good Guess. Anything is possible. Your ankle needs to evaluated both physically and with imagery. See a professional. Read more...
Yes. An ultrasound would show any ligament tear or rupture. MRI would show a talar dome injury. Start with an x-ray and evaluation by a Podiatrist. Ice will help with swelling and an ankle brace will help with stability. Read more...