4.1 Secret that Lies in Bones

Welcome back readers (:

Have you ever wonder, who are those people? And what are they doing there?

They are the FORENSIC ANTHROPOLOGISTS! err...

If you do not have any idea about it, keep on reading to find out more. (;

We are here to answer your questions. 

Ẅ͍́h͙͑a͍͌t̳͑ ̧́î̥s̩̒ ̠͒F͎͊o̢͊ŕ̝e̯͑n͈̐ş́i͓̚c͉͝ ̧̇Ạ͑n̟̚ť͍h̤̾r̳̕o̤̎p̳̋ȍ̠l̹͘ọ͠g̩̓y̥̽?

A combination of  theories and methods of anthropology, osteology and archaeology with legal investigations. 

R̳͝o̳͐l̥̾e͚̅?͙̒

1. Aiding in the collection & analysis of human remains
2. Identification of victims beyond recognition 

3. Estimation of time since death

4. Establishment of injuries and potentially cause of death. 

Well, anthropologists are frequently involved in non-criminal matters, especially as part of mass disaster teams. When natural disasters, plane crashes or explosions occur, you will find a lot of unknown victims requiring identification. 

H̦̏o̤̊w̞̒ ͇̅i̳͒t͈̂ ̞̇i̥̋s̮̓ ̫̈́d̩̃o̩͊ṋ̍ĕ̘?̨͂

So, it is done by the process of elimination. 

**Try not to know anything about the case to eliminates bias and avoid mistakes**

Here are some methods that will help you in the identification process. (:

Age of Remains
Carbon dating is a common method of establishing the age of bones or objects. The radioisotope carbon-14 is taken up by an organism in life. As the half life of carbon-14 is known as being 5,700 years, the amount of the isotope remaining in the sample can be used to calculate its age. 

Checkout this awesome video to see how Carbon-14 works!

Sex
Check out our previous blog post on the differences between male and female skull. 

http://dentalinvestigators.blogspot.com/2013/10/differences-between-male-and-female.html?zx=6c4b79f79f6b7d40

Besides the skull, the most obvious part is the pelvic bone!

Women generally have

• proportionally wider pubic bones to allow room for a baby’s head to pass through during childbirth. 
• sub-pubic angle of more than 90 degrees, while man is less than 90 degrees. 

So guys, dun ever complain about girls butt as they exist for a beautiful reason!

* This method is not a useful indicator when determining the sex of a pre-pubescent child, as the pelvic bone in girls is yet to widen. 

Picture adapted from:  http://biology.clc.uc.edu

Age

Ossification
Everyone of us underwent a process known as ossification in around 800 points around the body, in which separate pieces of bone fuse together! 

As the bones fuse together, sutures are formed in between them, appearing as ‘zigzag seams’. The fusion of particular bones generally occurs at specific points in an individual’s life, making them invaluable in age determination. The fusing of the epiphysis to the diaphysis of the bone are similar indicators of age. 

Growth centers within the limb bones allow the limbs to lengthen as the individual grows. Throughout this growth period, the epiphyses are soft, eventually hardening into bone and fusing with the main shaft as adulthood approaches. 

This is the process of ossification. (:
Picture adapted from: http://classes.midlandstech.edu/carterp/Courses/bio210/chap06/lecture1.html

Picture adapted from: http://fleshandbones1.blogspot.com/2010_04_01_archive.html

For examples

• At age 6, two bone plate form at either end of radius bone in arm
• At age 17 for males, 20 for females, lower plate fuses with radius, upper plate then follows
• At age 18-20, the head of the femur fuses
• At age 24, part of the hip undergoes the same process 
• Cranial sutures: At birth, the human skull is composed of numerous smaller bone segments to give the skull flexibility. As individual ages, ossification occurs. Extent of fusion is useful in age estimation (provided victim is under 30 years old)

Cartilage to Bone
Some sections of cartilage around body also gradually turn into bone over time, at a particular age. 

For example
At birth the wrists are composed of cartilage, eventually forming into bone. If the victim is under the age of 13, a wrist x-ray can often pinpoint the child’s age within a few months. 

X-ray showing the progression of cartilage turn into bone.
Picture adapted from: http://www.visualphotos.com/image/1x6007905/coloured_x-ray_of_hand_bone_growth_child_to_adult

Pubic symphysis: the midline joint between the left and right pubic bones. The two pubic bones, joined by cartilage, are characterised by a rough, uneven surface which gradually smoothens out over time. 

X-ray of pubic symphysis
Photo adapted from: http://www.e-radiography.net/radpath/d/diastasis_symphysis.htm

Osteon Counting
Methods: microscopy. The more osteons present in the bone, the older the victim.
**Osetons are minute tunnels within the bone housing nerves and nutrient-providing blood vessels. 

Picture adapted from:  http://legacy.owensboro.kctcs.edu/gcaplan/anat/notes/api%20notes%20h%20skeletal%20system.htm

Ethnicity
There are a number of differences in the structure and appearance of bones between individuals of different races, majority are based in the skull. 

Caucasian	Negroid	Mongoloid
Narrower face and more prominent chin	Outward-sloping jaws	Skull broader around the face, squarer & forward-sloping
Cheekbones fairly flat		Wing-like cheekbones
High-bridged nasal bone	Broader nose bridge with wider nasal openings and subnasal groves	Lower nose bridge
Upper incisors have flat lingual surface	Upper incisors have flat lingual surface	Upper incisors shovel-shaped

Negroid, Mongloid, Caucasian (from left to right), 
Picture adapted from : http://news.brown.edu/pressreleases/2009/01/race

**Racial determination is not always obvious, particularly with the increasing likelihood of mixed-race victims.  

Individual Differences
Adult woman: pubic bone, pregnant/victim has given birth in the past has wider pelvic inlet. 

Stature
If skeleton is whole, measure directly to establish the rough height. 
Otherwise, use  a formula.

• Human height is generally two and two thirds the length of the femur, taking into consideration slight variations due to race and sex. 

Weight
Well-developed muscles will leave clear markers on the bones around the muscles. The more they are used, the rougher the bone’s surface becomes to anchor the tendons of the muscle in use. 

Congratulation~~ you have finished reading this long post. haha. 
Hope that you learnt something new. (:

Good Luck

References:
http://forensicsciencecentral.co.uk/anthropology.shtml
http://anthropology.si.edu/writteninbone/index.html
http://www.theabfa.org/