Figure 1
![Figure 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1477-7827-2-44/MediaObjects/12958_2004_Article_169_Fig1_HTML.jpg)
Compact cumulus (A): tightly attached cells surrounding the oocyte with a smooth surface over the cumulus hillock. Expanded cumulus (B): cells detached from the oocyte with matrix visible between cumulus cells.
Compact cumulus (A): tightly attached cells surrounding the oocyte with a smooth surface over the cumulus hillock. Expanded cumulus (B): cells detached from the oocyte with matrix visible between cumulus cells.