There are lots of videos about ASL and medical signing on the web. Here are a few of my personal favorites. The signer in these 4 videos is an amazing model for pure ASL:

Eustachian tubes: https://www.youtube.com/watch?v=N0MumyP2jLQ 

Asthma: https://www.youtube.com/watch?v=N0MumyP2jLQ

How the Eye Works: https://www.youtube.com/watch?v=N0MumyP2jLQ

Nervous system: https://www.youtube.com/watch?v=N0MumyP2jLQ

This is a basic introductory video. This signer has a lot of videos on the web also. We used some of them in ASL 101.

Health Literacy – how to create materials that match the reading level of your patients