Cranial features and race27 Nov 2011
Individuals whose ancestry derives mostly from different parts of the world sometimes have different cranial features. Forensic anthropologists have studied these differences for many years, finding some that are especially useful for distinguishing ancestry. In American legal contexts, ancestry is usually at issue as a way of determining the racial affinity of unidentified skeletal remains. Hence, the forensic anthropologist usually tries to make a determination as to whether a skull has features that indicate African, European, Asian or Native American ancestry.
Cranial features are not perfect indicators of ancestry: Forensic anthropologists using multiple features claim at best 85% accuracy in their assessment of racial ancestry. When we know less about the context of a skull, we will be less and less accurate.
Here are some traits that vary between skulls with different race backgrounds. Most of them are on the face or palate.
- Shape of the eye orbits, viewed from the front. Africans tend to a more rectangular shape, East Asians more circular, Europeans tend to have an ``aviator glasses'' shape.
- Nasal sill: Europeans tend to have a pronounced angulation dividing the nasal floor from the anterior surface of the maxilla; Africans tend to lack a sharp angulation, Asians tend to be intermediate.
- Nasal bridge: Africans tend to have an arching, ``Quonset hut'' shape, Europeans tend to have high nasal bones with a peaked angle, Asians tend to have low nasal bones with a slight angulation.
- Nasal aperture: Africans tend to have wide nasal apertures, Europeans narrow.
- Subnasal prognathism: Africans tend to have maxillae that project more anteriorly (prognathic) below the nose, Europeans tend to be less projecting.
- Zygomatic form: Asians tend to have anteriorly projecting cheekbones. The border of the frontal process (lateral to the orbit) faces forward. In Europeans and Africans, these face more laterally and the zygomatic recedes more posteriorly.
What to do: This station includes several casts representing skulls of different ancestries, along with one ``mystery skull’’. Examine the features that vary by ancestry in this skull, comparing it with the others. Can you assess the racial origin of the mystery skull?