How accurate is facial reconstruction in forensics?
okkkk. I did a big project on this... and here's some of my research... let's hope it answers your question



Facial reconstruction (also known as craniofacial identification) is a method used in the forensic field.  Many people view facial reconstruction as an art instead of science.  Art is commonly portrayed as the expression or application of human creative skill and imagination, typically in a visual form such as painting or sculpture, producing works to be appreciated primarily for their beauty or emotional power.  Science is thought of as the intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment.  But where do science and art blur the lines?

WHAT CAN WE TELL FROM THE SKULL:

The skull provides clues to personal appearance. The brow ridge, the distance between the eye orbits (sockets), the shape of the nasal chamber, the shape and projection of the nasal bones, the chin's form, and the overall profile of the facial bones all influence facial features in life. Using these bones, artists and forensic anthropologists work together to reconstruct facial appearance through the process of forensic facial reconstruction.  There are many ways of telling both the approximate age, and the approximate ethnic background of the victim.  To find age, you can pay attention to the cranial suture (or the place where the cranium fuses to other bones of the skull), the size of the skull can help, as well as the teeth and the formation of the bottom jaw.  When looking for the birth gender of the victim, scientists often pay attention to the brow ridge, eye sockets, mandible, and the slant of the jaw.  Sometimes, it is impossible to tell by looking at the skull what birth gender the victim was.  In cases like this, people look to the pelvis to tell if the human has given birth, and if not, males do not have a ventral arc.  It is often very difficult to find the race of a victim if they are mixed race, or if the skull is very worn out.  However, to find the ethnic background scientists will look at the shape of the skull, the nazel root, and the space between eye orbits. 

WHAT ARE THE PROCESSES OF FACIAL RECONSTRUCTION AND ARE THEY ACCURATE:

Facial reconstruction is an exacting process. The finished product approximates the actual appearance, because the skull does not reflect the details of soft tissues-eye, hair, and skin color; facial hair; the shape of the lips; or how much fat tissue covers the bone. Yet, facial reconstruction can put a name on an unidentified body in a modern forensic case, or, in an archaeological investigation, a face on history.

Today, many forensic facial reconstruction techniques are in use, including two-dimensional (drawn), three-dimensional manual and three-dimensional computer-based.  In the manual techniques, including two dimensional a cast of the skull is required, so the facial markers do not become an anomaly when analyzing the skull.  Although all of these methods are used, it is most common that a trained sculptor, who is familiar with facial anatomy, works with a forensic anthropologist and uses clay to build the facial features. The forensic anthropologist interprets skeletal features such as the subject's age, sex, and ancestry, and anatomical characteristics such as facial asymmetry, evidence of injuries (a broken nose, for example), and loss of teeth before death. 

Facial reconstruction is used when the victims dental records fail to identify them, and there is no dna to pull from the body.  The process of reconstruction starts with making a mold of the unknown skull with the jaw attached and false eyes in place.  Depth markers are placed on 21 different “landmark” areas of the mold of the skull to approximate the facial tissue thickness that lay on the skull.  These tissue thicknesses are approximated from averages of other people of the same age, sex, and race as the skull is assumed to be.  Facial muscles are placed on the mold next and then the face is built up with clay to within a millimeter of the depth markers as tissue.  The nose and eye setting are very difficult to estimate due to the enormous amount of variation possible, mathematical models are used to make the approximations, the mouth is assumed to be the same width as the distance between the pupils. In facial reconstruction the eyes, nose, and mouth are mostly guess work.  Characteristics such as birthmarks, wrinkles, scars, and such are guesses at best and cannot actually be determined from the skull.  Facial reconstruction is accurate because it has been using mathematics, and calculations as such, in order to determine spaces, amounts, as well as the shapes of the face themselves. 

WHY IS FACIAL RECONSTRUCTION IMPORTANT:

Facial recognition, as well as facial reconstruction is very important in the forensic field.  Both have a very important role in catching murderers, and investigating crime.  Without having a facial reconstruction, often times, you cannot identify victims.  Assuming the body is historical and for museum purposes, then without an identity it becomes very difficult to fill in large gaps of information, and time that can be crucial to history.  Also, if you can’t identify a murder victim then scientists could only look into cause of death.  Learning the identity of a deceased victim is as important to crime investigations as learning the identity of the suspect. When human remains are found, then the top priority is often to find the identity of the victim.  Police often also will look for an identity out of respect, for both the victim and the victim’s loved ones if any.  Facial reconstruction has been used ever since 1890.  Before 1890, people mostly used few facial indicators such as the shape of the frontal bone, and the remains of flesh to help identify the victim.  Facial reconstructions, can also show what injuries were sustained previous to death.  

WHAT CAN WE LEARN FROM FACIAL RECONSTRUCTIONS:

Our skeleton is an extensive record of our lives. The food we eat, the rate at which we grow as a child, the injuries we sustain, whether we have given birth; all can be determined from our bones. Experts can determine sex, age, and ethnicity, relatively easily from the skeleton, with the skull and pelvis playing pivotal roles in this analysis. Later this week, we’ll be taking a more detailed look at how to determine sex and ethnicity from a skull.Teeth can reveal information about diet and a comparison between dental records of the deceased and the recovered skull is often the primary method of identification.  By looking at the scull (or any bones in fact,) you can tell childhood injuries from injuries that might have been fatal.  You can also look at bone density and other factors to tell if the victim was suffering from any diseases.  People look for the sagittal suture – the squiggly line that runs the length of the skull – If it is fully fused, the remains are likely to be of someone older than 35. After that professionals look for a second line at the front of the skull -- the coronal suture – which fully fuses by age 40. Teeth are also looked at. If they're worn down it could be a sign of a poor diet. If they're well-maintained and/or have good dental work such as fillings, they were able to afford proper dental care—another clue as to the identity of your skeleton. Oftentimes professionals consult a scientist who specializes in teeth, known as an odontologist. They can determine how old a person was at death, what kind of health they were in and what kind of diet they had.

Baby's bones begin to grow in the womb. At birth, the skeleton is partially formed. Many bones are still in "parts." The ends (epiphyses) and bony shafts (diaphyses) of long bones form separately in the womb. At birth, the ends of the long bones are mainly cartilage, with centers of bone beginning to form inside. As a child grows, the shafts get longer, and bone gradually replaces the cartilage epiphyses. Through the growing years, a layer of cartilage (the growth plate) separates each epiphyses from the bone shaft.  By paying attention to this, it is easier to tell age, and follow growth patterns to have a successful reconstruction.  

Between 17 and 25 years, normal growth stops. The development and union of separate bone parts is complete. At this point, you and your skeleton are as tall as you are going to get - with many fewer bone parts than you started with.  The bones that enclose the brain grow together during childhood along lines called cranial sutures. During adulthood, bone "remodeling" may gradually erase these lines, at variable rates. Closure of cranial sutures gives general information about a person's age. It is best used with additional indicators to estimate age, or when other age indicators are unavailable.  

WHAT ARE THE LIMITATIONS:

It is very hard to estimate a person’s weight and represent that with facial markers.  Since a chart of average thickness of soft tissue is used to estimate the way a person looked, if you were on the skinnier side, your head might appear a lot more overweight than usual and or skinnier.  To help determine weight, scientists look at the rest of the remains for a height.  Facial reconstruction relies on the relationships between the facial features, subcutaneous soft tissues and underlying bony structure of the skull. If there is no clue for potential identity because of impossibility to compare questioned remains with possible familiar material, in such cases one of the last chances is to recreate ante mortem appearance by face reconstruction. Many of the soft tissue thickness values are significantly different from those reported for comparable groups, suggesting that individuals from different geographical areas have unique facial features thus requiring population-specific values. This literature review attempts to throw some light on the important aspects that has to be taken into consideration while setting norms of soft tissue thickness among various populations. 

Studying the unknown skeletal remains mostly becomes the only way to find out more information about individual characteristics, which could lead to identification of potential victim. If there is no clue for potential identity the most precise comparative techniques fail, because of impossibility to compare questioned remains with possible familiar material. In such cases one of the last options is to recreate ante mortem appearance by face reconstruction. Following the first introduction of reconstruction in the late 19th century, other techniques have been developed including radiography, 3D statistical model, ultrasound, MRI, CT and Cone Beam Computed Tomography (CBCT).  Facial contours were traditionally considered to be the result of positioning of underlying hard tissue followed by the soft tissue. However, current trend shows a paradigm shift from the conventional hard tissue analysis to also include both hard- and soft-tissue analysis.

IS FACIAL RECONSTRUCTION AN INTERDISCIPLINARY ART:

The skull is made up of 22 bones, 14 of those are facial and eight are cranial bones; it is a complex structure, and small variations during development and growth, together with soft tissue differences, create the enormous facial variation seen in the human population.  Artists have long been interested in the direct anatomical relationship between the skull and facial appearance.  

Artist, Gaetano Guilio Zumbo (1656-1701), used facial reconstruction as an art because he believed that math and science are both forms of art.  His work can be found in the Wax Anatomical Collection at La Specola Museum, Florence, became famous for his macabre scenes depicting various stages of decomposition of the human body.  One of his most famous pieces is the head of a dead man, with facial muscles recreated in wax over a real skull.
This is the earliest surviving anatomical wax model created for didactic purposes and exhibits extraordinary anatomical precision alongside an artistic sense of horror and decay. Although we assume that Zumbo was less concerned with facial appearance than anatomical detail, he pioneered the development of scientific art and this work ranks as one of the finest examples of three-dimensional facial reconstruction. 

By definition, an interdisciplinary art is relating to more than one branch of knowledge.  Facial reconstruction is often categorized as both a science and a mathematical equation.  Both science, math and art are human attempts to understand and describe the world around us. The subjects and methods have different traditions, and the intended audiences are different, think the motivations and goals, specifically for this purpose is fundamentally the same.