Attribution of Sex Activity

The analytical stage of forensic anthropology involves answering questions that lead to identification of the individual whose remains are being examined. The questions asked in developing a biological or demographic profile for an individual include the following:

  • What is the ancestry of the individual?
  • What is the sex of the individual?
  • What is the age of the individual?
  • What is the stature of the individual?
  • What pathologies did the individual have?
  • What traumas did the individual have?

The sex of an individual is determined, when soft tissue is not present, by a number of skeletal indicators. Of course, the more indicators used to determine sex, the more accurate the results. However, a forensic anthropologist is analytically limited by the bones present and the condition of the bones.

We will look at several features of the pelvis, skull, and limb bones in determining sex. What we will do in this activity for sex determination does not cover all skeletal indicators of sex, but it will give you a good idea of how a forensic anthropologist determines the sex of an individual using the bones. The most accurate assessment of sex can be derived from the complete skeleton, followed in accuracy by the pelvis, skull, and then individual postcranial bones.

Remember that sex determination is very difficult for sub-adults because those features and characteristics are not fully formed, thus giving a more gracile appearance. Unless specified, the elements in the photos are Caucasoid.

The measurements used for this activity are not inclusive of all the measurements that are normally collected by anthropologists from complete specimens. The measurements used here are introduced and discussed in your text (Byers, 2011).

Assignment: Determination of Sex

Compare the elements (and/or measurements) in the activities below to the known pelvic bones and skulls in the reference materials. Based on the sex model, determine the sex for each specimen.

Assessment Dropbox.


You will identify the sex of three individuals in this assignment. Often, remains exhibit characteristics that can be attributed to both sexes. In these cases, assign the sex to the group that has a majority of traits.

Part I. Non-Metric Traits

Anthroposcopy, or the study of non-metric traits, is used in attributing sex. In this part, you will be looking at several different characteristics of the pelvis and the skull to estimate sex of two individuals.

The non-metric traits in the table below are a collection of the different methods that forensic anthropologists use. Your text covered the material as one set, but I have separated them here according to their developers. Note: there will be some overlap and there maybe one or two characteristics not described in your book (you should still be able to identify the characteristics by what you have learned).

Note: Zoom in the document if you want a closer look at a particular feature. You may have to look at multiple images to identify a trait.

Refer to the charactersitics in the Actvity Reference Materials and your textbook for help.

Pelvis 1

female ischiopubic ramus .jpg On the answer sheet, use the highlight function to highlight all the pelvic traits that you observe in Pelvis 1, and make a final count at the end. Then identify sex (and why) in the space following Table 1.

Figure 1 Medial view of Left ischiopubic ramus (left); Figure 2 Anterior view of Left os coxa (above)

Figure 3Lateral-Posterior view of Left os coxa

Figure 4 Anterior view of os coxea

Figure 5 Anterior view of Right subpubic concavity (above); Figure 6 Anterior view of Left pubis (below)

Figure 7 Distal view of Left os coxa showing sciatic notch (above)

Table 1 Sex Characteristics of the Pelvis

Phenice(1969)Not present/ SmallPresent/ Large 
Ventral Arc

Medial aspect of



Ischiopubic Ramus                                                          and Sharp


Sutherland &                                                                      Narrow,               Wide,

Suchey (1991)

Pubic Body

rectangular        square

Subpubic Angle                           Narrow                     Wide


Trait                                                 Male                                                    Female

From Brothwell (1981);

Ubelaker (1978)

Illiac Blades (Illium)                    High, not flared (vertical)             Flared laterally, (low/flat)

Greater Sciatic NotchConstricted, approx. 30° angleWide, approx. 60°
Preauricular SulcusShallow, if presentDeep, if present
Obturator foramenLarge, ovoidSmall, triangular
Subpubic AngleAcuteObtuse
Ventral ArcRidge not presentRidge is present
Subpubic ConcavitySlight depression, or absentLarge concavity


Pelvis 1 Results:

Cranium 1

On the answer sheet, use the highlight function to highlight all the skull characteristics that you observe on cranium 1, and make a final count at the end. Then identify sex (and why) in the space following Figure 8.

Table 2 Characteristics of Male and Female Skulls

Trait   Male Female Frontal Bone   Steep, rugged,slanted Rounded, smooth Supraorbital Ridge/ Brow ridges Prominent, large Smooth, gracile, sharp       boarder, or none Supra-Orbital Margin   Rounded, blunt superior margins Sharp margins Size   Large and rugged Small and smooth   Chin     Broad, Flared>125°, wide, square   Pointed, Narrow <125°, constricted Mastoid Processes   Thick, thumb-like Smaller, finger-like Occipital Protuberance/ Nuchal Crest   Marked muscle ridges, thick, with hook Not marked, does not protrude   Result:         Cranium

From Krogman (1962:115);

Brothwell (1981:59)

Lateral (right) view of cranium 1

Anterior view of cranium 1

Cranium 1 Results:

Part II. Metric Traits – Cranial measurements

Like the discriminant functions used to attribute ancestry, discriminant functions can be used to separate between male and female using measurements of the skull.

Cranium 2

For this section, identify and enter the values in the appropriate rows for Cranium 2 into Table 6 below. Also enter in the appropriate discriminant function measurements (discriminant function of your choice) for White crania. Then identify sex (and why) in the space following Table 6.

Each measurement is multiplied by its coefficient, and all such calculations are summed to arrive at a function score. These scores are compared with the sectioning points in Table 5 to attribute sex.

Function values that fall below the sectioning point are female while those above the sectioning point are male.

Note that the functions use different sets of measurements. As stated in your text, this is to accommodate incomplete crania.

These measurements would under normal conditions be taken with sliding or spreading calipers.

Table 4 shows how your calculations should look like. The cranium measurements used for Table 4 belong to Black ancestry and using Discriminant Function 9.

Figure 10 Views of skull showing measurements used in discriminant functions

Table 3 Cranial Measurement Descriptions

BaPrBasion to prosthion
MLMaximum length: from the glabella to the occipital bone (measuring the greatest distance)
MBMaximum Breadth: from highest points on squamosal suture (measuring the greatest distance)
BaBrBasion to bregma
BaNaBasion to nasion
BBBi-zygomatic breadth: perpendicular to the sagittal plane
NaAlNasion to lowest point in the alveolar border between central incisors
PBMaximum breadth of the palate
LMLength of the mastoid process (measured from the upper border of the external auditory meatus)

Note: All measurements should be recorded in mm

Table 4 Example of attributing sex using discriminant function 9

MeasurementValue Coefficient Calculation
BaPr       xxx      X =xxx
ML       188      X3.533=664.204
MB       135      X1.667=225.045
BaBr       140      X0.867=121.38
BaNa       108      X0.1=10.8
BB       142      X8.7=1235.4
NaAl       xxx      X =xxx
PB       xxx      X =xxx
LM        30        14.367 431.01
Sum————–——————-  2687.839
  Sectioning Point  ———  —–  ——————-      2515.91

Table 5 Discriminant Functions for Determining Sex of White and Black Crania


Table 6

Measurement BaPr ML MB BaBr BaNa BB NaAl PB LMValue                                                                                                                                  X X X X X X X X XCoefficient                             =                             =                             =                             =                             =                             =                             =                             =Calculation                                                                                                                                                                                                                                                                                                 
Sum Sectioning Point Discriminant Function Number: 

Cranium 2 Results:

Part III. Final Assessment

Briefly write your conclusion (minimum 300 words) on the three methods used to attribute sex (skull metric vs. pelvic non-metric vs. skull non-metric). Which method did you think was more accurate? And why? Offer examples.


Byers, Steven (2011) Introduction to Forensic Anthropology (4th ed). Prentice Hall.

France, D. L. (2003) Lab Manual and Workbook for Physical Anthropology (5th ed.). West / Wadsworth. White, T. D. (1991) Human Osteology. Academic Press.

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