Estimating Sex Flashcards
What is sex based on?
chromosomes and sex hormone proportions
What is gender based on?
socially prescribed and perceived identities
Can you estimate gender from a skeleton?
No!
Sexual Dimorphism
physical differences between the sexes of different species
How can we estimate biological sex from the skeleton?
size and shape differences
Broadly, what do female bones usually look like?
smaller and more rounded
Broadly, what do male bones usually look like?
larger and more robust
Can you estimate sex from juvenile remains?
No! (sexual dimorphism starts around puberty)
Human variation ___.
is not discrete (happens on a scale)
Increased disease in a population leads to ___ dimorphism in a population.
decreased
How accurate is using the skull and pelvis together for estimation? `
90-100%
How accurate is using the pelvis alone for estimation?
90-95%
How accurate is using the skull along for estimation?
70-87%
How accurate is using long bones alone for estimation?
~80%
Why is the pelvis so good for estimating sex?
its under two very important evolutionary constraints that limit variation (walking & childbirth)
Why do bones belonging to males have more muscle attachments?
Increased testosterone = increased muscle = increased weight = increased muscle attachments
Male v. Female: Pelvis Inlet & Outlet
male: heart-shaped inlet (more closed in), female: circular & oval-shaped
Male v. Female: Pelvis Blades
male: high and vertical, female: low and wide
Male v. Female: Sacrum
male: long and narrow (tucks in more), female: short and wide (less curvature)
What is Phenice’s Method?
the most well known method for sex estimation
What traits is Phenice’s Method based on?
ventral arc, subpubic concavity, and ishiopubic ramus
Male v. Female: Ventral Arc
male: triangular, female: little corner (more square)
Male v. Female: Subpubic Concavity
male: straight, female: concave
Male v. Female: Ischiopubic ramus
male: wide and dull, female: narrow and pinched
What is the scoring for phenice’s method?
1 (female, 2 (indeterminate), 3 (male)
What is the significance of the additions by Bulkstra and Ubelaker?
they were included in the 1994 “Standard for Data Collection from Human Skeletal Remains” which was made due to the passing of the NAGRA act
What two additional traits did Bulkstra and Ubelaker add?
Sciatic notch and Preauricular sulcus
Male v. Female: Sciatic notch
Male: narrow
Female: wide
Male v. Female: Preauricular sulcus
Male: no sulcus
Female: well-developed sulcus
What are three other traits to look out for?
pubic shape, subpubic angle, and obturator foramen
Male v. Female: Pubic shape
male: triangular, female: rectangular
Male v. Female: Subpubic angle
male: v-shaped, female: u-shaped
What is the name of the attempt to use metrics to estimate sex?
the ischiopubric index
What does the ischiopubric index measure?
the length of the pubris / the length of the ischium
Why is the ischiopubric index difficult to work with?
it is very difficult to find the correct and accurate measurement point as the os coxae is very weird and has no consistent landmarks
On average, individuals with a higher ischiopubric percentage are …
female
What are shape differences btwn the sexes in the cranium due too?
size differences
True or False: Some methods for estimating sex work better for specific populations than others
TRUE
Male v. Female: nuchal crest
male: rugged & hooked, female: small to none
Male v. Female: mastoid process
male: large & projecting, female: small & non-projecting
Male v. Female: supraorbital margin
male: rounded, female: sharp
Male v. Female: glabella
male: large, female: small
Male v. Female: mental eminence
male: massive & well-defined, female: minimal
Significance of Giles and Elliot’s method?
used discriminant functions to determine sex based on metric methods
What is the sectioning point?
the metric point that differentiates between females and males when using discriminant/regression functions
What are the 4 steps for using Giles and Elliots method?
- Select appropriate function
- Measurement x coefficient
- Add resulting values
- Compare to sectioning point
True or False: Methods using multiple postcranial measurements can be more accurate than cranial methods.
TRUE
What is best practice when it comes to using cranial and postcranial methods?
use different methods in different regions of the body to see if they align
What are the important measurements from the scapula?
scapular max length & height of glenoid fossa
What are the important measurements from the humerus?
vertical head diameter
What are the important measurements from the radius?
maximum head diameter & minimum head diameter
What are the important measurements from the femur?
head diameter
Why is the Terry Collection not great for estimating sex?
the collection is old and does not include Latinx individuals
What are the contributions of Spradley et al?
found many postcranial methods used do not work well for Hispanic populations (2008), created new equations for sex estimation of Hispanic populations using postcranial measurements (2015)
Why does ancestry play such a big role in estimating sex?
different bones are different depending on population
What are the two spreadsheets used for morphoscopic trait sex estimation?
Klales et al (pelvis) and Walker (skull)
