How can I create a form that I partially populate and send to others to add to?

Is this possible with JotForm?

I want to create a form that is used for medical case reviews. I would enter some information about the visit then send to others who would review the case and then enter their responses. 

Yes, this is possible with Jotform. You have two options here.

If you do not want to submit the form, you can prepopulate the fields and send the prepopulated form by email. Our Prepopulate Fields app would help you generate the URL: https://prepopulate.jotform.io/.

You can also submit the form, and get used of our Edit Submission feature. Guide below:

https://www.jotform.com/help/40-How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date

But instead of adding the link in the autoresponder email, add it to the notification email template. In that template, add the others as your recipient so once they receive the email, they can click the link to fill out their part.

If it's a workflow with approvals, we have a guide for that. Check our guide below for the steps:

https://www.jotform.com/help/432-A-General-Approach-on-Building-an-Approval-Process-Workflow