Just about everyone has twisted an ankle at one time or another; ankle sprains are the most common athletic injury. However, if they're not treated right away and completely rehabilitated before you return to action, they can become a chronic problem. 
The ankle is a complicated hinge joint composed of four bones and four major ligaments. The bones are connected by the ligaments, fibrous tissue that gives the joint stability. The ligaments will tear if their range of movement is exceeded. A sprain can range from mild to severe, resulting in equivalent amounts of instability in the ankle.
The most common ankle sprain is an inward twist, with the foot turning underneath the ankle. The three lateral ligaments of the ankle may be so severely torn that you're unable to bear any weight on the injury. Or the sprain might be so mild you can "walk it off" and continue your activity. In either case, proper treatment and rehabilitation are essential to prevent a chronic problem from developing. The initial treatment for all sprains is RICE: Rest, Ice, Compression and Elevation.
Rest Rest the injured ankle, avoiding any activity that causes further pain. Meanwhile, you can maintain conditioning with activities that won't stress the joint, such as riding a stationary bicycle, using a rowing machine or swimming with leg floats.
Ice Apply ice as soon as possible.
Ice decreases pain immediately by numbing the skin and reduces swelling by constricting blood vessels. Much of the pain from an injury is caused by swelling from torn blood vessels. Controlling the swelling helps you make a speedier recovery.
It's best to use crushed ice in a watertight bag covered with a thin cloth so it's not too cold against the skin. Apply it for 15 minutes directly over the area of swelling. Longer applications may cause a rebound dilation of the blood vessels and may actually increase swelling.
Apply the ice every four to eight hours as long as the swelling continues (even as long as a week). You can use chemical ice packs, but many experts warn that because they do not melt the same way as ice, they can overcool the ankle and cause a chemical freeze to the skin.
Compression
Compress the swollen area with an elastic bandage. Begin the wrap at the toes and continue it up about four inches above the ankle. If you begin the wrap above the toes, all the swelling is likely to accumulate in the toes. 
Don't wrap it so tightly that it causes more pain or cuts off the circulation to your toes. While the elastic wrap can reduce further swelling, it usually doesn't provide enough support to prevent reinjury.
Elevation
Elevate the injured ankle as much as possible, particularly while applying ice; this allows gravity to drain some of the swelling. Place the ankle higher than the knee, the knee higher than the hip and the hip higher than the heart. Use books, a suitcase or a box under the mattress at night; this works better than a pillow.
What Next?
Once the swelling is controlled, the next step depends on the severity of the injury. A severe sprain may need to be casted. If you're unable to bear weight on it, or you hear a pop at the time of injury or there is a great deal of swelling and pain, the ankle may be fractured or unstable. In any of those cases, consult a physician.
X-rays should be taken if you can not walk four steps.
They should also be taken if you have tenderness over the bony prominences at the sides of your ankle or the bones in your feet. If the X-rays do not show a fracture, then you have a sprain. The amount of recovery time you need will depend upon the severity of the sprain and your rehabilitation program. If you're able to bear weight without pain and if swelling and bruising are limited, you can start rehabilitation immediately. 
Begin with non-weight-bearing range-of-motion exercises. While sitting, flex the ankle up, pulling gently with a towel. Then push your foot downward against gentle pressure from the towel. You also can flex the ankle to 90 degrees and then press isometrically to the right and left.
It's extremely important not to limp when you walk and bear weight on an injured ankle, even if it is necessary to use crutches. If you walk with a limp, the position-sensing nerves in the foot quickly forget the correct way to walk and instead learn to limp. Subtle changes in this function can leave you with a chronically imbalanced ankle that is easily reinjured.
Practice walking with a normal heel-toe motion, even just after your injury if you can't walk normally avoid walking at all, because you may be doing further damage. Instead, try rolling a large can using a heel-to-toe motion while sitting. Use crutches to help you walk without a limp, or rest the ankle further.
Rehabilitation
Treating the pain and swelling is just the first step on the road to recovering the full strength and range of motion in your ankle. Rehabilitation includes a complete series of exercises to regain flexibility and to strengthen the ankle and foot to prevent reinjury.
The most effective program is one designed specifically for you and your injury by a certified physical therapist or athletic trainer.
How can you tell when you're ready to return to your sport? Ligaments will usually heal within four to eight weeks, but your comeback may be limited by an underlying weakness of the lower leg muscles and tightness of the Achilles' tendon.
Be sure to stretch the Achilles' tendon and strengthen the lower leg muscles by doing the dorsiflexion (toe raises) and eversion (twisting your ankle outward) exercises.
Most experts agree that chronic ankle injuries result from improper rehabilitation of a previous injury. You must have full range of motion around the joint without pain before returning to the complicated movements in running.
Test yourself first by standing on the sprained ankle alone for two minutes. If you are able to do this without wobbling too much, try walking on your heels for 50 steps, then try a straight-ahead jog.
The ultimate test is to run in a figure-eight pattern. If you can do all of these activities without experiencing pain, you're ready to return to action.
What follows are some exercises you can do to strengthen your ankle and assist in rehabilitating the joint.
Even with the best rehabilitation, some injuries don't heal completely. You may need to use some support for the ankle whenever you participate in sports. Most trainers and physicians agree that taping provides the best support. Some new lace-up and inflatable ankle braces are also showing promise.
With RICE treatment and a proper rehabilitation program, you can soon be up and running again.
Here are some exercises to strengthen your ankle.
Resistive Plantarflexion
For these exercises, you'll need a fairly strong elastic belt or other firm but stretchy material. Hold one end of elastic in your hand and loop other end around foot. Now push foot down against resistance of the elastic.
Resistive Dorsiflexion
Place one end of elastic under the leg of a heavy piece of furniture or other firm support. Sit on floor facing furniture legs straight out in front of you. Loop other end of belt around the top of your foot. Now, try to flex your foot toward your body and against the resistance of the elastic.
Resistive Eversion/Inversion
Sit as described for Resistive Dorsiflexion, toe pointing to ceiling. Turn ankle outward without rolling leg and press for 30 seconds. Then turn ankle inward and press for 30 seconds.
Treatment:
1.Signoflam thrice daily
2.Ranitidine thrice daily
3.ice pack
4.compression bandage
5.rest for 7 days
6.Keep foot elevated while resting.