Secrets that bones tell part 2

Determining Age from Bones How did researchers determine the age of ‘the crossbones girl’? What other ways do our bones change as we age? Forensic anthropologist Dr. Bill Bass holds an adult femur and an infant femur

Age & Epiphyseal Plates 1.Epiphyseal Plate Fusion  The long bones grow in length from cartilage plates (called growth plates or epiphyseal plates) found on each end of the bone.  On one end of the epiphyseal plate, cartilage grows. On the other end, cartilage is replaced by bone. Throughout childhood, the rate of these two processes is equal.  In late adolescence, the growth of the cartilage stops. Bone continues to replace the cartilage plate until it is gone. At this point, the person’s long bones can no longer grow. Cartilage is shown in blue Epiphyseal caps

Age & Epiphyseal Plates  A person’s age can be determined by analyzing whether the epiphyseal caps are completely separated from the diaphysis by cartilage, partially fused (some cartilage remains, but bone connects the epiphyses to diaphysis) completely fused Cartilage is shown in blue Epiphyseal caps The state of fusion can be seen from physical examination of the bones from X ray older

Age & Epiphyseal Plates

Ring finger of boy age 0 to age 19

Age & Epiphyseal Plates

Bones fuse at different times for different people, but investigators can narrow the possible range of ages by examining multiple bone markers. Forensic investigators examine a skeleton and find that the following bones have fused. What are the possible age ranges? Fused: Humurus (both ends), radius (proximal end) Unfused: all the others

Age & Epiphyseal Plates Bones fuse at different times for different people, but investigators can narrow the possible range of ages by examining multiple bone markers. Forensic investigators examine a skeleton and find that the following bones have fused. What are the possible age ranges? Fused: Humerus (both ends), radius (proximal end), femur (both ends), tibia (both ends), clavical (distal end) Unfused: radius (distal end), clavicle (proximal end) 19-20

Age & Epiphyseal Plates Bones fuse at different times for different people, but investigators can narrow the possible range of ages by examining multiple bone markers. Forensic investigators examine a skeleton and find that the following bones have fused. What are the possible age ranges? Fused: Humerus (both ends), Unfused: everything else

Age & Epiphyseal Plates Bones fuse at different times for different people, but investigators can narrow the possible range of ages by examining multiple bone markers. What is the upper limit for the usefulness of epiphyseal plates in estimating age? 30 Which leads us to our next indicator of age …

Age & Cranial Sutures When we are born, our skull consists of 5 separate flat bones, separated by fibrous material called sutures. The sutures allow our heads to expand as we grow. The sutures close in young to middle-aged adulthood, as our bones grow together.

Age & Cranial Sutures Completely intact sagittal suture Partially closed sagittal suture Completely closed sagittal suture age

Age & Cranial Sutures Completely intact sagittal suture Partially closed sagittal suture Completely closed sagittal suture GenderSagittal suture completely open Sagittal suture completely closed All sutures completely closed MaleYounger than 32Older than 26Older than 35 FemaleYounger than 35Older than 29Older than 50 Ages associated with cranial suture status What is the likely age range are of a male skeleton with an open sagittal suture and fused clavical epiphyseal plates?

Age & Cranial Sutures Completely intact sagittal suture Partially closed sagittal suture Completely closed sagittal suture GenderSagittal suture completely open Sagittal suture completely closed All sutures completely closed MaleYounger than 32Older than 26Older than 35 FemaleYounger than 35Older than 29Older than 50 Ages associated with cranial suture status What is the likely age range are of a female skeleton with closed sagittal suture and unfused proximal clavical epiphyseal plates?

Age & Joint Morphology Middle and older ages can be determined, within a range, by changes in joints shape that occur throughout life. The joint that is used most often is the pubic symphysis. Joints exhibit wear, flattening, and rimming with age

Age & Teeth Teeth are the best evidence for determining the age of children, as they have regular patterns of eruption. Dental records can also be extremely useful in identifying individuals; especially after events like fire.

Age & Teeth Teeth are the best evidence for determining the age of children, as they have regular patterns of eruption. What is the likely age of a baby who has all four central incisors, but no other teeth? What is the likely age of a baby who has all its baby teeth except the second molars? 8 – 12 mos. 17 – 31 mos.

Age & Teeth Teeth are the best evidence for determining the age of children, as they have regular patterns of eruption. What is the likely age range of a child who has lost their central and lateral incisors, but no other baby teeth? What is the likely age range of a child who lost all its baby teeth except the second molars? 6 – 11 years. 10 – 12 years

Bones & Trauma Bones also provide a record of traumas that occurred both well before (antemortem) and around the time of (perimortem) death. Gunshot wounds

Bones & Trauma Bones also provide a record of traumas that occurred both well before and immediately before death. Blunt force trauma

Bones & Trauma Bones also provide a record of traumas that occurred both well before and immediately before death. Fractures

Estimating Height with Linear Regression The length of the long bones (especially the femur, tibia, and humerus) correlates height. Thus, researchers can estimate the height of a person if they find even one of the major long bones. Researchers have collected height and bone length data from hundreds (thousands?) of people. They use linear regression to find a line that best fits the data. The line equation can be used to predict the height of a person based on bone length. The R 2 value describes how well the line predicts height – the higher the R 2 the better the prediction is likely to be.

Estimating Height with Linear Regression Estimate from graph If a femur is 27 cm, how tall is the person likely to be? What is the likely minimum and maximum height? Estimate using equation If a femur is 24 cm, how tall is the person likely to be? 155 cm = 5’1” 169 cm = 5’6” Roughly 164 – 174 cm