My grandson has what the doctor said was trigger finger of his thumb. My son had it a few years ago but he was an adult and he was told it was because he was using his hand too much in the same motion again and again – and it wasn’t his thumb. Since my grandson is only 9 months old, how can he have trigger finger? Is it from sucking his thumb?

Doctors don’t know what causes trigger finger, although they do know that adults who use the same movements frequently can develop it over those who don’t. However, in children, trigger finger is particularly puzzling. At one point, doctors felt that it may be something the child is born with, a congenital problem, but that has since been discounted. Now, there are several other theories, but one is that it is caused by the bent shape most children keep their thumb.

When a child sucks his or her thumb, it is usually kept straight, so it’s unlikely that this would be a cause.