Secrets That Bones Tell (part 2) Guided Notes
Name ____________________
Predicting Age – Epiphyseal Plates

The long bones grow in length from cartilage plates (called _________________________ or
________________________) 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.

A person’s age can be determined by analyzing whether the epiphyseal caps are


------------------------------------------------------------- from the diaphysis by cartilage,

______________________________________(some cartilage remains, but bone
connects the epiphyses to diaphysis)

_______________________________________
The state of fusion can be seen from

physical examination
of the bones

from X ray
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?
1.
Fused: Humurus (both ends), radius (proximal end)
Unfused: all the others
2.
Fused: Humerus (both ends), radius (proximal end), femur (both ends), tibia (both ends),
clavical (distal end)
Unfused: radius (distal end), clavicle (proximal end)
3.
Fused: Humerus (both ends),
Unfused: everything else
4.
What is the upper limit for usefulness in using epiphyseal plate fusion to determine age?
Predicting Age: Cranial Sutures
When we are born, our skull consists of 5 separate flat bones, separated by fibrous material called
___________________________. The sutures allow our heads to expand as we grow.
The sutures close in young to middle-aged adulthood, as our bones grow together.
Completely open sagittal suture
Completely closed sagittal suture
1. What is the likely age range are of a male skeleton with an open sagittal suture and fused clavical
epiphyseal plates?
2. What is the likely age range are of a female skeleton with closed sagittal suture and unfused proximal
clavical epiphyseal plates?
Predicting 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
Predicting Age: Tooth Eruption
Teeth are the best evidence for determining the age of children, as they have regular patterns of eruption.
Dental records are also extremely using for identifying a person, especially after disfiguring events such as fire.
1. What is the likely age of a baby who has all four central incisors, but no other teeth?
2. What is the likely age of a baby who has all its baby teeth except the second molars?
3. What is the likely age range of a child who has lost their central and lateral incisors, but no other baby
teeth?
4. What is the likely age range of a child who lost all its baby teeth except the second molars?
Identifying signs of trauma from bones
Bones also provide a record of traumas that occurred both well before (antemortem) and around the time of
(perimortem) death.
Estimating height from bone length
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 ___________________________________________ to find a line that best fits the data.
The ____________________________ can be used to predict the height of a person based on bone length.
The __________________ describes how well the line predicts height – the higher the R2 the better the
prediction is likely to be.
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?