Sex determination - lecture 1

  1. what is sex vs gender
    sex= biological

    gender= socially constructed
  2. how many pairs of chromosomes does each human cell have?

    which chromosomes determine primary sex determination?

    X & Y chromosomes

    • male XY
    • femal XX
  3. what is the phenomena by which males and females display basic differences in size and and shape?

    In general males...?

    In general females?
    Sexual dimorphism

    Males: larger with more developed musculature

    females: have anatomical traits related to childbirth esp. in pelvis
  4. How much earlier does adolescent growth spurt occur in girls?

    When do major differences emerge?
    2 yrs

  5. Where are differences in pattern and timing of growth most apparent?
    pelvis and skull
  6. In terms of age influence in trait expression, when are triats fully i.e skeltal growth completed?
    mid to late 20's (esp for males)
  7. Young ___ can look more ____ esp in skull
    Young males can look more feminine esp. in skull
  8. Skulls of post-_____ females can have a more _____ appearence due to lack of _____/______ ofsetting natural levels of testosterone
    Skulls of post-menopausal females can have more masculine apprerearence due to lack of estrogen/progresterone offsetting natural levels of testosterone
  9. When examining whole skeleton, sex acccurately estimated 90-100% of cases

    just pelvis - ___%
    just skill ____%
    just long bones ____%
    pelvis 90-95%

    skull 80-90%

    just long bones - 80%
  10. Pelvis

    Males :

    Males = large and rugged

    Females = small and gracile
  11. Ilium


    Males -high and vertical

    • Females- low and flat
    • Image Upload 1
  12. Subpubic angle in pelvis

    v-shaped = m/f?

    u-shaped = m/f
    V shaped = male

    U Shaped = female (female more curvy UUUU)

    Image Upload 2
  13. Pubic shape


    Males -Broad and square

    Females -narrow and rectangular
  14. Pelvis

    Circular/elliptical = m/f

    heart shaped = m/f

    male (heart shaped)

    Image Upload 3
  15. Obturator foramen in pelvis


    Males - large and ovoid

    • females - small and triangular
    • Image Upload 4
  16. Greater sciatic notch

    Preauricular sulcus
    • Females : wide greater sciatic notch,
    • well -developed preauricular sulcus

    • Males : Narrow greater sciatic notch
    • rare preauricular sulcus
  17. Shape of sacrum


    Male - long and narrow

    Female - short and broad
  18. Phenice traits

    accuracy =

    What are the three phenice traits?

    • Ventral arc
    • Males = slight/absent
    • Females- strong

    • Subpubic concavity
    • Male - convex
    • Female - concave

    • Ichiopubic ramus ridge
    • Male - area broad and flat
    • Female- narrow, crest-like ridge
  19. What is Washburn's ischum pubic index? (what does it quantify?)

    what is the equation?
    Quantifies longer, more stretched aspect of pubic bone in females when compared to males

    • <84 = male
    • >94 = female
    • --> this is only 68% accurate but 83-91% accurate if ancestry known
  20. Shulter-Ellis et als DISCRIMINANT FUNCTION?
    Image Upload 5
  21. Anthroscopic traits of the skull?

    Size  - male vs female

    Chin - Male vs female

    • m- large and rugged
    • f- small and smooth


    • m-broad
    • f-pointed
  22. Mastoid process


    Male - large and projecting

    Female - small, non projecting
  23. Frontal skull
    Supraorbital margin
    Brow ridges
    • Male - slanted
    • Female - high, rounded

    • Male - rounded
    • female - sharp

    • Male - large
    • Female - small non

    Image Upload 6
  24. Nuchal area

    • Male - rugged, may have hook
    • Female - smooth, hook rare
    • Image Upload 7
  25. What was Walkers logistic discriminant functions, what did it predict?
    predicted sex of skulls via trait scores
  26. What did Giles and Elliots discriminant function measure i.e what did they use??

    what was the accuracy an among what group of people?
    mastoid length, bizygomatic width, max.length, max breadth of skull

    85.5% accuracy for black and white population
  27. Juvenile sexing is very difficult, When are differences most visibly seen?

    there are substle differences during 5th month inutero due to?

    at 8 weeks in utero?
    Foetuses, infant and young children < 5 yrs (the younger the better)

    differences in testosterone levels.

    testosterone levels in male foestus rise and remain high until birth after which levels falla dn remain low until puberty
  28. What is schutkowski's method for juvenile sexing based on?

    degree of accuracy?
    morphological features of the pelvis and mandible

  29. Juvenile sexing

    What are 3 mandibular traits in juveniles to look for?
    • -Protrusion of chin
    • - male promominant females not
    • -shape of anterior dental arcade-
    • males wide, females rounded contour
    • -eversion of gonion 
    • males everted, females not
  30. Pelvis traits in juveniles

    angles of sciatic notch in males vs females?
    Male ~ 90 degrees

    females > 90 degrees
  31. Pelvis traits in juveniles

    arch criterion, males vs females
    Males -  extension of vertical side of sciatic notch leads into lateral rim of auricular surface

    females - arch formed by drawing extension from vertical side of sciatic notch, crosses auricular surface
  32. depth of sciatic notch in females vs males (juveniles)
    males - deep

    females - shallow
  33. curvature of iliac crest in juveniles
    - males vs females
    males - viewed from - S shape

    Females viewed from top - faint S shape
  34. What post cranial bone can be measured to determine sex? (3)

    what part of this bone is measured?
    Fermur, Clavicle, scapula

    • Femur:
    • -Measuring vertical head diameter
    • -Measuring bicondylar width
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Sex determination - lecture 1
sex determination - lecture 1