What’s wrong with Teddy’s shaky hind legs?

Hello, first, the dog lack of calcium caused by the owner can give the dog to eat some calcium food, you can let the dog more sun and exercise to help it replenish calcium; second, the dog bones have problems resulting in hind legs shaking, the owner needs to take the dog to the animal hospital to do a specific examination to determine the specific cause. Third, a certain situation of fear of nervous reaction.