Christina Alonso

Session 4

Septal Apertures and non metric traits

What is a non metric trait?Traits that are not

measured Sometimes they are

noted as a presence/absence trait, but are ofter not as simple as presence/absence (Mizogouchi 1985)

They can be bilateral (occuring on both right and left sides) (Finnegan 1978)

Non metric traits are highly susceptible to environmental influences, dental traits are not

• Metopic suture• Inca bones• Mastoid foramen• Septal aperture

They can be used to help gauge affinity of human populationsMigration of certain groups

Dental traits are the most widely used (successful) skeletal indicators of population affinity

Why are these traits important?

Septal Apertures

•What is it? – a perforation in the lamina that seperates the coronoid and the olecranon fossae

•more common in women than men, and more common on the left side

•May predispose people to low energy fractures of the distal humerus

•Silviera (2007) noted that the midshaft diameter was smaller in bones that had the aperture (but the research was not published)

•Is it inherited, or is it hyper mobility of the joint?

Septal Apertures

What might cause them?

Over mobility of the joint(some of the apertures are so big the

Some think it is bone resorption from the anterior part of septum

Some think the aperture actually leads to strengthening the bone

Basically, each paper contradicts the one before it

No real pedigree studies have been done

Why are they important?

•They can help to estimate group affinity• Tell us which people might have migrated here• Tell us which populations could be related

• 5-10% in European populations• Almost 60% in North and West African groups• 8.7% in an English sample from Wharram Percy

(mediaeval)

Can this non-metric trait help us to track migration on this island?

We need more information, and more research done on this pathology…