Selecting one block in a collection

Selecting one block in a collection

I have a structure of similar blocks
      - all containig a clickable image
      - each identified by a unique hidden index
I want to find the value of that index when clicking on the image
The code is something like :
  1. <div class="bloc">
        <p class="enTete">
            <img class="modif" src="monImage">
            <input type="hidden" value="1" />
        </p>
        <div class="content">
            Contenu
        </div>
    </div> <!-- End bloc 1 -->

    <div class="bloc">
        <p class="enTete">
            <img class="modif" src="monImage">
            <input type="hidden" value="2" />
        </p>
        <div class="content">
            Contenu
        </div>
    </div> <!-- End bloc 2 -->

    <div class="bloc">
        <p class="enTete">
            <img class="modif" src="monImage">
            <input class="index" type="hidden" value="3" />
        </p>
        <div class="content">
            Contenu
        </div>
    </div> <!-- End bloc 3 -->






























How can i write the selector to read the right index when one the image is selected ?
Somethig like : (The '?' means I dont find how to do !!!!)
  1.     $(' ? .modif').click(function() {
            test = $(' ? .index').val();
            alert(test);
        });