Determining Age-At-Death in the Human Skeleton: Adults Only

Today’s blog post is a continuation of a previous piece wherein forensic anthropological methods for sexing the human skeleton were addressed.  In this segment an explanation of how to determine age-at-death in adult skeletons will be addressed.  Before you read any further you must be aware that this is not going to be a comprehensive explanation but a summary/overview of the methods.  You will not learn enough to pass an exam or become an expert in human osteological analysis.  

Figure 1: Cranial sutures examined to determine age-at-death (Buikstra & Ubelaker, 1994)

 

There are two ways adult skeletons can be analyzed to determine age-at-death: morphological analysis of the cranial sutures or the pubic symphysis.  Neither of these methods will provide one with an exact age-at-death estimate down the year, but they can narrow down either broadly or a little more narrowly the likely age of the victim (e.g. young, middle, or old adults and 20-25 versus 45-50 years of age).  The cranial suture method provides a broader age estimate and can be used on both sexes, whereas the pubic symphysis method can provide a narrow age estimate but the methods are sex specific.

 

Figure 2: Anatomy of the pelvic girdle (Allen et al.)

 

The cranial suture method involves examining at the suture lines of the skull (Figure 1).  Sutures are junctures where the cranial bones meet up, and over time they begin to fuse and obliterate (disappear).  It is this fusion process that allows for the age-at-death determinations to be made.  Open sutures are often found in younger adults, whereas obliterated sutures are associated with older adults.  Those within partially fused sutures are considered middle aged adults.  Fusion/obliteration of the cranial sutures are, however, sensitive to various environmental factors, and therefore this method should be used with caution as it is considered less accurate than the pubic symphysis aging method.

 

Figure 3: The Todd standard for determining age-at-death in the pubic symphysis

 

The pubic symphysis aging method involves examining the surface of the pubic symphysis, the connection point where both pelvic bones meet (Figure 2).  These bones never fuse together and instead remain connected by cartilage.  Over time, the billowing surface of the pubic symphysis dissolves, causing the bone to appear shriveled or shrunken in appearance.  Based on the process of morphological change one can identify the age of death a little more precisely by either using the Todd (Figure 3) or Suchey-Brooks (Figure 4) methods.  These are two separate methods that utilize the pubic symphysis in estimating age but produce slightly different age estimates.  Neither standard is believed to be affected by pregnancy or birth, which was believed to cause damage to the pubic symphysis, but as both standards are derived from homogeneous, modern populations it is unclear how applicable this aging method is to ancient or diverse populations.

 

Figure 4: The Suchey-Brooks standard for determining age-at-death in the pubic symphsis

 

Again, these methods are exclusively used for estimating age-at-death among adult skeletons.  There are separate methods for determining age-at-death for juvenile skeletons.  This blog post is not a comprehensive review of the method but a summary of the methods available.

 

References

Buikstra, J., & Ubelaker, D. H. (1994). Standards for Data Collection from Human Skeletal Remains: Proceedings of a Seminar at the Field Museum of Natural History. Arkansas Archeological Survey.

White, T. & Folkens, P. (2005). The Human Bone Manual. Academic Press.