If a toddler hits the back of the head after a fall, when should you call the dr, if at all, if there are no signs of injury?

Toddlers fall a lot as they learn to walk and manage their environment. You'll have to consider how hard he fell and was it blunt or a sharp corner and is there a knot or bruise and what part of his head. Kids are pretty indestructible--lots of bumps and tumbles and scrapes and owies. Heads are pretty well protected by the skull, though babies' skulls are softer than adults'. I'd probably call the dr's office and at least report it happened and ask for their take on it, especially if he hasn't hit his head before this.

To start with any head injury can be dangerous. If you notice motor skills not working properly, for example: not walking well , when reaching for something not able to grab it the first time. Also, eye pupils of different sizes, one eye seems to be out of align with the other. Fever. Speech not as good as usual. If any doubts carry your child to the doctor, or call and tell them of any symptoms.