Human Bone Analysis
What Can Archaeologists Discover from Human Skeletons?
Human bone analysis is a vital part of archaeology. By analysing the appearance and chemical composition of bones various types of information can be revealed about people’s lives in the past. However, it is a technique that must be used with care.
Age, sex, diet, disease and lifestyle can be determined in the following ways:
Age.
- Bone fusion. Bones pass through various stages before becoming fully fused in adulthood. These stages help identify how mature an individual was at death. The collar bone is one of the last bones to fuse at 26, the base of the spine or the sacrum between 16 and 23. Full skull fusion is normally only complete in full grown adults but skulls can still be used for gauging approximate ages in adolescents by looking at the thickness of the bone which increases with age.
- Teeth. The stage of dental development is a good indicator of age; i.e. the stage of tooth eruption in the dental sequence. Also, the development of ridges in enamel growth can give an approximate idea of age at death. Teeth in the past often became worn down and heavily eroded due to the high proportion of grit in the milled flour. The more eroded the teeth, the older the individual. Bone microstructure: Young bones have rings about their circumference. These disappear as the individual ages.
- Levels of Citrate: This chemical is found in high proportions in female bones between puberty and the menopause so.
Sex
It can be difficult to sex juvenile bones. In adults, the following can indicate whether adult remains are male or female:
- Bone size. Male bones are generally longer and larger than female and have more obvious muscle markings.
- The skull. Males have bigger skulls with more prominent brow ridges and mastoid processes (bumps behind the ear.) They also tend to have bigger jaws.
- Pelvis. This is the best indicator of sex as the pelvic cradle is wider in female than males.
- Levels of citrate. Adult female bones show higher levels of this chemical than male bones because of the female hormone cycle.
Height
- Bone length: Height can be determined from complete leg and arm bones.
Diet
- Analysis of carbon isotopes or trace elements in the bones such as strontium which can which food types were most commonly consumed i.e. was a diet predominantly vegetarian, maritime or meat based. It is also possible to differential between cereal and non cereal based diets.
- Nutritional deficiencies can also be detected from the appearance of bones. Curved leg bones indicate lack of vitamin D during childhood. Holes in bones can indicate anaemia indicting a lack of green vegetables of red meat. Flat bones indicate a diet deficient in protein
- Harris lines: these are calcium formations which relate to periods of arrested growth during childhood or adolescence, commonly because of illness or malnutrition. Clearest in the lower shin bone.
Disease and Damage
- Stresses on different bones can be used to indicate common activities performed in an individual’s lifetime. Deformed ankle bones indicate constant squatting, whereas degeneration of the lower spine is indicative of individuals carrying heavy loads.
- Lesions on bones indicate overuse of certain muscle groups. On arms this could indicate common use of bows or throwing spears whilst on feet it indicates a lot of running.
Certain diseases also leave their marks on the skeleton:
- Arthritis-most common affliction
- ealed by the joints
- Teeth cavities-indicate a high carb diet.
- Infectious diseases. Only one 1% can be identified from human bones. Leprosy, TB and syphilis show up most clearly in human bones, with leprosy eroding the bones of the face and syphilis leaving pitted bone structure.
- Congenital defects such as spina bifida and Sprengel’s Deformity also show up in the bones.
Restrictions and limitations
Much of the basis of human bone analysis is based on the model of the modern Caucasian skeleton. However, variations can occur over time and in different world populations. In some parts of the world, female pelvises are narrower than their European counterparts. Likewise, they have been found to have larger skulls. Australian aborigines, Africans and Asians have differing body proportions to each other which have to be taken into account when calculating height from leg bones. As a basic rule, bones found in a given region need to be compared against each other to establish if the individual represents the exception or the norm and to establish information about whole societies.
Finds are also useful in establishing context with regard to bone analysis and lifestyle. It is not possible to say that bone lesions were caused by hunting activities if there is no evidence of hunting activities with the body or in the area it was buried.
Finally, bones found are not necessarily representative of a whole society. Certain bones may not have survived time or soil conditions. Different classes may have been buried separately meaning a burial sample isn’t fully representative of a society.
Whether using human bones to analyse individuals or groups, context is key.
Sources
Archaeology: An Introduction (1995) Kevin Greene. B T Batsford Limited. London
Archaeology: Theories, Methods and Practice (1994) Colin Renfrew and Paul Bahn.Thames and Hudson.
What do you think about this article?
More in History
Latest Articles