Get values of all POST checkboxes in array via PHP?

I'm making a form that allows the user to check where they want certain push notifications to go. There is multiple checkboxes that get POSTed in PHP. Here is my PHP snippet:

if(isset($_POST['Submit'])) {
function sendMessage(){
    $pushmessage = ($_POST['PushMessage']);
    $content = array(
    "en" => $pushmessage
    );

foreach($_POST['formDeliver'] as $check) {
        $segments = $check; 
    }

$fields = array(
  'app_id' => "app-id-here",
  'included_segments' => array($segments),
  'data' => array("foo" => "bar"),
  'contents' => $content
);

Edit: Here is my checkbox code:

      <input class="LCB" type="checkbox" id="district" value="All" name="formDeliver[]" checked><label class="light" for="district">District-Wide (Everyone)</label><br>
      <input class="LCB" type="checkbox" id="high" value="High School" name="formDeliver[]"><label class="light" for="high">High School</label><br>
      <input class="LCB" type="checkbox" id="middle" value="Middle School" name="formDeliver[]"><label class="light" for="middle">Middle School</label><br>
      <input class="LCB" type="checkbox" id="williams" value="Williams Ave." name="formDeliver[]"><label class="light" for="williams">Williams Ave.</label><br>
      <input class="LCB" type="checkbox" id="norwoodv" value="Norwood View" name="formDeliver[]"><label class="light" for="norwoodv">Norwood View</label><br>
      <input class="LCB" type="checkbox" id="sharpsburg" value="Sharpsburg Elementary" name="formDeliver[]"><label class="light" for="sharpsburg">Sharpsburg Ave.</label><br>
      <input class="LCB" type="checkbox" id="athletics" value="Athletics" name="formDeliver[]"><label class="light" for="athletics">Athletics</label>

Whenever the form is submitted, the $fields array submits the message info. I need to pass the segments (values of the checkboxes) as a string like this: "String 1", "String 2", "String 3". Whenever i do this, however, it only grabs the last ticked checkbox and submits it into the $segments variable. Is this something I'm doing wrong or not seeing?