Not playing Hamlet, but working with a skull.
You’re beavering away in your laboratory, DNA-ing this, mass-spectrometer-ing that, when the samples from the new crime scene come in. This time (to your relief) it’s fairly clinical: no blood and gore today. It’s a simple skull. The cops at the scene need to know as much about it as soon as possible; without you, they’re clueless. An initial observation doesn’t reveal much and it’s going to take a while to get dental impression results back.

Until then, what can skull analysis tell you? Quite a lot actually, but let’s start by determining the sex of your unfortunate victim.

 

The long bones and short of it.
Forensic anthropologists are trained to “read” skulls: they whisper silently to the contributing factors of death or trauma to the head. Here, we’re more concerned about questions of identification, and so we’ll acquaint ourselves with the external features of the skull.

Each individual’s skull is more or less different: yours will differ wildly to mine – including variations in cheekbone depth or height, thickness or thinness or other idiosyncrasies of size and shape. Such features that vary between individuals are called nonmetric features and are not normally measured.

 

Sexing skeletons
In the case of a long-decomposed and unidentified individual with no other affects on their person (e.g. a driver’s license or a passport), an anthropologist must make a quick inference as to what sex the person is. To this end, we’ve compiled a quick-and-easy guide to determining the sex of an unidentified person, using only their skull.

 

1. Examine the features of the skull.


Men generally tend to have thicker, heavier skulls. They are typically notably larger than female ones, generally speaking. Although this factor will not determine sex on its own, combined with the other features outlined below, it can give you a good indication of gender.

 

2. Look to the temporal lines.


The temporal muscle is a long band of tissue stemming from the parietal bone on the skull, and extending all the way to the mandible (the uppermost part of the jaw). The part of the skull where the muscle attaches (the temporal line) often has a more pronounced ridge in males than females.

 

temporal_muscle
The indentation lies under the muscle in this rendering.

 

3. Look me in the eyes and say that.


The eye socket area, when looking at the skull, is referred to as an orbit. The lower section of the orbit differs slightly between men and women. Women have a sharper ridge and males a slightly blunter surface to them.

 

4. Underneath the arches.


The superciliary arch or “monkey brow” is not very prominent in humans. Think of the prominent forehead of our primate friends and you’re probably thinking of this arch. It exists above the orbits, and comprises two arched elevations which are prominent medially. In males, there is usually some slight ridging here and you should be able to see some of it. In females, there is typically very little, or none at all.

superciliary arches
A page out of the old Gray’s Anatomy to help you locate the arches.

 

A word of warning, if you please.
You shouldn’t rely on one of these features in isolation to determine gender, but should look to a combination of the factors to give you a reliable indicator.

Sure enough, the differences between male and female skulls may be subtle and require a preriod of “calibration” in order to become proficient in seeing the differences. Once this is done, you should have a fairly well-honed ability to determine the sex of an individual from their skull.

 

Your Turn: There are other methods to discover it out there, but we’ve shown you what we think are the easiest. Know of any others? Tell us all about it in the comments.

About The Author

Forensic Outreach has long been a dynamic and active part of classrooms throughout the United Kingdom and Europe. It was conceived as part of UCL’s Widening Participation programme in 2002 to introduce forensic science as an integrative and cross-disciplinary approach to science education.

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