Bootstrap 3 Skeleton

This is a simple Bootstrap skeleton. You can fork it to get a ready to use Bootstrap fiddle.

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/2.1.0/bootstrap.min.js"></script>
<div class="dropdown">
  <a data-toggle="dropdown" href="#">Dropdown trigger</a>
  <ul class="dropdown-menu" role="menu" aria-labelledby="dLabel">
    ...
  </ul>
</div>

<div class="dropdown dos">
  <a data-toggle="dropdown" href="#">Dropdown trigger</a>
  <ul class="dropdown-menu dos" role="menu" aria-labelledby="dLabel">
    ...
  </ul>
</div>

CSS

@import url('http://getbootstrap.com/dist/css/bootstrap.css');

.dropdown-menu:before {
  position: absolute;
  top: -7px;
  left: 9px;
  display: inline-block;
  border-right: 7px solid transparent;
  border-bottom: 7px solid #ccc;
  border-left: 7px solid transparent;
  border-bottom-color: rgba(0, 0, 0, 0.2);
  content: '';
}

.dropdown-menu:after {
  position: absolute;
  top: -6px;
  left: 10px;
  display: inline-block;
  border-right: 6px solid transparent;
  border-bottom: 6px solid #ffffff;
  border-left: 6px solid transparent;
  content: '';
}

/*Mi Estilo*/
.dropdown-menu.dos {
    top: 0;
    margin: 0 0 0 22%;
}
.dropdown-menu.dos:before {
    display: none;
}
.dropdown-menu.dos:after {
  content: "";
  border-right: 6px solid #000;
  border-top: 6px solid transparent;
  border-bottom: 6px solid transparent;
  position: absolute;
    left: -13.4px;
  top: 8.5px;
}