Anatomy

Dead Men DO Tell Tales: Determining Age, Sex, and

Paleopathology of the Human Skeleton

Based on workshops by Valerie Dean O’Loughlin, Ph.D. Assistant Professor of Anatomy

Indiana University and

Tori Randall, Ph.D. Professor, San Diego City College

Anthropologist, San Diego Museum of Man

Determination of Sex • Male and female human skeletons differ both in

general shape and size. However, patterns of sexual dimorphism can vary among groups.

• For example, male Asian skeletal remains can be less robust than female Native American skeletal remains.

• Thus, one cannot use size as the only factor to determine sex. The most reliable indicator of sex is the os coxae (hip bones), followed by the skull.

Tips to keep in mind

• Multiple features on each bone can be used to determine sex.

• It is common for some of these features to appear more “male” and others “female” – if this happens, sex is determined by the greatest number of features. For example, if the skull demonstrates 4 male-like traits, and 7 female-like traits, then you would classify the skull as females.

• It is difficult to impossible to determine the sex of infant and juvenile remains. Most infant/juvenile remains appear “female-like” until well after puberty.

• Sex determination should be made with respect to the general size/ robusticity patterns of the population from which the skeletal remains came.

• Like reading an EKG, determining sex of a skeleton is an art. It takes great practice to precisely determine sex.

Os Coxae Feature Male Characteristic Female Characteristic Superior Inlet Heart shaped Spacious, wide and oval General Size More robust and muscle-marked Less robust

Obturator Foramen Larger and oval Smaller and triangular

Acetabulum Larger, directed more forward/ Anteriorly

Smaller, directed more Laterally

Greater Sciatic Notch Narrow and deep Wide and shallow

Body of Pubis Short, triangular Longer, more rectangular

Subpubic Angle (area underneath the two pubic bones)

Narrow, V-shaped Broader, more convex

Preauricular Sulcus (depression between greater sciatic notch and sacroiliac articulation)

Usually absent Usually present

Sex Differences in Os Coxae

Aging by Pubic Symphysis

• The surface of the pubic symphysis undergoes changes as we age.

• It has proven to be a good, reliable indicator of age.

• Typically, the young adult pubic symphysis appears billowed and rugged, but by age 35 it becomes more worn and develops a rim.

• After age 35, the surface further erodes and degenerates.

Skull Feature Male Characteristic Female Characteristic

General size More robust More gracile/delicate

Nuchal Crest (prominence on back of skull, in occipital region)

Well-demarcated nuchal lines and a prominent bump or “hook”

External surface of occipital bone is smooth, with no bony projections here

Mastoid Process Large, projects below the external auditory canal

Smaller

Supra-orbital margin (upper orbit rim)

Thick, rounded, blunt border

Thin, sharp border

Supra-orbital ridge (“brow ridges”)

Prominent Little or no prominence

Mental Eminence (chin)

Squarish, greater forward projection

More pointed (versus squarish), little forward projection

Gonial Angle (side of jaw angle)

Flared, Less obtuse, <125 degrees (typically, about 90 degrees)

Typically > 125 degrees

Sex Differences in the Skull

Determination of Age • There are many methods to determine the age at death

of a skeleton.

• Some of these methods work best for juvenile/ immature remains, whereas others may work best for adult skeletal remains.

• Classes commonly used for skeletal remains: 1) fetal (before birth), 2) infant (birth – 3 yrs), 3) child (4-12 yrs), 4) adolescent (13-19 yrs), 5) young adult (20-34 yrs), 6) middle adult (35-49 yrs), 7) old adult (50+ yrs)

Aging by the Skull • After the os coxae, the skull (cranium plus

mandible) is the next most reliable structure from which to determine the sex.

• The skull exhibits a varying degree of sexual dimorphism.

• However, this dimorphism can vary from population to population.

• Thus, one should realize that sex determination from the skull is dependent upon the population.

Aging by Cranial Suture Closure • Cranial sutures fuse progressively as one ages. • Typically, the anteriorly-placed sutures (coronal) fuse

first, followed by the more posteriorly-placed sutures (i.e., sagittal and lambdoidal, respectively).

• However, there is considerable variability in closure rates, so this aging method should be used in conjunction with another methods.

• One cranial feature that has a high reliability rate is the spheno-occipital synchondrosis (at the base of the skull), which fuses between 20 and 25 years for over 95% of populations studied.

Composite score Mean Age Standard Deviation (yrs) 0 --------------- ----------------- 1-2 30.5 9.6 3-6 34.7 7.8 7-11 39.4 9.1 12-15 45.2 12.6 16-18 48.8 10.5 19-20 51.5 12.6 21 --------------- ---------------------

The figure below shows the 10 areas where sutures should be examined. Each suture should be graded with the following scale: 0=open suture, 1=minimal closure, 2=significant closure of suture, 3=completely obliterated suture. The numbers should be added together and a raw “score” is given, which with the two tables, could be used to estimate age.

Other Age Determination Methods

• Subadult/Juvenile remains can be aged with the following methods:

• Dental eruption • Epiphyseal union • Dental attrition (wear) – sometimes

• Adult remains can be aged with the following methods:

• Dental attrition (wear) • Cranial suture closure • Pubic symphysis changes

Aging by Dental Eruption Aging by Epiphysial Fusion Determination of Stature • There is a correlation between long bone length

and stature. • This correlation varies among populations; even

between males and females. • Researchers have used skeletal remains from

modern populations to develop “formulas” to estimate stature.

• Formulas are both sex and population dependent. • It is unclear what error is introduced when these

formulas are used with archaeological specimens

• The following table lists formulas for three populations.

• All measurements of the bones should be maximum length measurements.

• These bone measurements preferably should be taken with an osteometric board.

• Of the bones listed, the femur typically provides the most accurate stature estimation.

Paleopathology • The study of diseases in ancient populations, as

revealed by skeletal remains.

• While many pathologies can be detected in the skeleton, these cases typically represent the more severe forms of pathologies.

• For example, only the more severe cases of tuberculosis will leave evidence of such on the skeleton. Thus, when examining evidence of pathology in skeletal remains, one must realize that some less serious forms will not be detected.

Paleopathology • What are some pathologies/anomalies that can be detected

in the skeleton? • Trauma (recent or healed fractures, dislocations, subluxations) • Some infectious diseases, like tuberculosis, osteomyelitis (infection/

inflammation of the bone), leprosy, syphilis, other infections • Metabolic/nutritional disorders, like scurvy, rickets, osteoporosis,

osteomalacia • Blood (hemopoietic) disorders, such as anemias, leukemias

(sometimes), myelomas • Endocrine disorders, such as pituitary gigantism, dwarfism • Benign and malignant tumors • Arthritis (osteoarthritis, gout, rheumatoid arthritis, ankylosing

spondylitis which causes the characteristic ‘bamboo spine’) • Caries (cavities) and other dental pathologies • Skeletal dysplasias, such as achondroplasia (dwarfism), osteogenesis

imperfecta (characterized by numerous fractures) • Scoliosis (lateral curvature of spine), kyphosis (increased anterior

curvature in thoracic spine)

Cancer

Acromegaly Trephination

Cultural Modification

Leishmaniasis Thalassemia Osteoblastic Meningioma

Syphilis Syphilis

Syphilis Syphilis Exostosis or Surfer’s Ear

Exostosis or Surfer’s Ear Tuberculosis Tuberculosis

Trauma Amputation Infection