Although we don't know the complete context of this photograph, it was taken during the last several days in Egypt during what has been a largely nonviolent revolution. As we watch and hold our collective breaths, as it is certainly a complex and ongoing process, I want to take this opportunity to evaluate a very particular facial expression. Let me call your attention to the woman in the red sweater.
The woman we're examining displays a classic (although not fully pronounced) sign of pain - which very intriguingly is common to both emotional pain and physical pain. Her central forehead shows partial contraction while her peripheral (outer) forehead is relaxed. This is somewhat difficult to see. If it were more pronounced, we would see a classic upside-down horseshoe-shaped pattern of furrows in her central forehead with the outer forehead still being relaxed (unfurrowed).
Her central eyebrows are also elevated, which also coexists with the above mentioned forehead pattern. This is also classic for both physical and emotional pain. Her eyebrows are also pulled together - which is often coexistent with vertical furrows between the eyebrows. Another feature of sadness we see here - is her drooping upper lids and down-gazing eyes.
Moving further down her face, we see that her mouth is opened. Additionally, while the corners of her lips are pulled down her cheeks are being simultaneously raised. There is a tension between this downward pull of the mouth's corners with the upward pull of the cheek muscles - as demonstrated by a deepening and downward extension of the nasal-labial furrow. Additionally, parallel facial furrows, although often not as pronounced become visible in the lower, peripheral face. Chin dimpling is also common.
As in most body language photographs I discuss, this display of emotion is a more extreme example - thus these serve as great teaching tools. However, compared with what we see on most days in our everyday lives - it is much common to see mild emotional examples - and it's these displays that are nearly always missed. It is imperative that you see these subtle emotions when they surface - and certainly never misinterpret them. This is what most people do far too often. Don't be most people.