anthropology

life after death
demographic estimation from the skeleton

Estimating age from the skeleton

Skeletal age is the estimated age at which a person died. Skeletal age can be determined by looking at the following:

sutures of the skull
teeth
ribs
vertebrae
growth areas of the long bones

Sutures of the Skull

When a baby is born, the skull is still growing. To accommodate this growth, the different bones of the skull are separate. By the age of 7, all the different bones have finished growing and the fontanelles have disappeared.

Extreme unfused sutures

Teeth

The first teeth to appear are the incisors, which are followed by canines and molars. When chewing food, teeth grind down. Comparing different teeth gives an idea of how long the teeth have been used. Eventually all teeth are lost, due to caries or attrition.

Milk Teeth Permanent Teeth

Incisors 7 months to 1 year Incisors 6.5 years

Canines 2 years Canines 10.8 years

Premolar 1 none Premolar 1 10.4 years

Premolar 2 none Premolar 2 11 years

Molar 1 3 years Molar 1 6.2 years

Molar 2 3 years Molar 2 12.2 years

Molar 3 none Molar 3 18 years

Milk Teeth	Permanent Teeth
Incisors	7 months to 1 year	Incisors	6.5 years
Canines	2 years	Canines	10.8 years
Premolar 1	none	Premolar 1	10.4 years
Premolar 2	none	Premolar 2	11 years
Molar 1	3 years	Molar 1	6.2 years
Molar 2	3 years	Molar 2	12.2 years
Molar 3	none	Molar 3	18 years

Ribs

Because of breathing, the front part of the ribs is constantly moving. As a person gets older, the front part of the ribs begin to change and form bony spikes.

Sternal ends of ribs

Vertebrae

As a person gets older, bony spikes can also start growing on the vertebrae. This starts at approximately 40 years of age.

Ostheophytes on lumbal vertebra

Growth areas of the long bones

From birth to ±25 years of age, a person grows at a relatively constant rate. This rate of growth is known. Growth takes place at the ends of the long bones. At a certain age, growth is completed and this can also be seen on the bone.

Growth areas on the femur and tibia

The upper arm stops growing at the shoulder at approximately age 20 and at the elbow at approximately age 14.5. The upper leg stops growing at the hip at approximately age 17.5 and at the knee at approximately age 18.

Estimating sex from the skeleton

In general, the muscles in a man are stronger and more developed than in a woman. Bones of men are larger and more robust than bones of women. Some bones display specific features which can be used to help determination of the sex of the skeleton. The best indicators are the:

Skull
Pelvis
Head of the Femur

Skull

The brow-ridges, which are above the eyes, are larger in a man than the brow-ridges in a woman. The forehead of a man slopes more than the forehead of a woman. The edge of the eye-socket of a man is round while the edge of the eye-socket in a woman is sharp.

Male browridges Female browridges

Male Female


Male	Female

Pelvis

Women give birth. For this reason, the pelvis of a woman is larger than the pelvis of a man. The pelvis of a woman is wide and circular whereas the pelvis of a man is narrow and heart-shaped. Two angles, the sub-pubic angle and the sciatic notch, cause the differences in the shape of the pelvis. In women, the sub-pubic angle and sciatic notch are wide. In men, the sub-pubic angle and sciatic notch are narrow.

Narrow subpubic angle in male pelvis Wide subpubic angle in female pelvis

Male Female


Male	Female

Head of the Femur

In men, the diameter of the head of the femur is larger than 51 mm. In women, the diameter of the head of the femur is less than 45 mm.

Female femur head

Disease in the skeleton

Inherited Disease - unfused vertebrae
Dental Disease - Cavities, Abscesses, and Attrition
Trauma - Fractures, Head Injuries

Joint Disease - Arthritis
Infectious Disease - Periostitis
Disease - Osteoporosis and Cancer