INTRODUCTION

The analytical stage of forensic anthropology involves answering questions that lead to identification of the individual whose remains are being examined.  The questions asked in developing a biological or demographic profile for an individual include the following:

• What is the race of the individual?
• What is the sex of the individual?
• What is the age of the individual?
• What is the stature of the individual?
• What traumas did the individual have?
• What pathologies did the individual have?
• What idiosyncratic traits did the individual have?

OBJECTIVES

• To use the hand lens for magnified examination of skeletal traumas.

• To examine and describe skeletal traumas.

• To practice carefully handling skeletal material.

READINGS

• Review Chapters 11, 12, 13, and 14 plus pages 363-366 in the Byers text.

• Review the trauma handouts given in lecture; bring them to lab.

• Review Chapters 11, 12, 13, and 14 in the Byers lab manual.

TERMS

• trauma
• bone fracture
• blunt-force trauma
• sharp-force trauma
• gunshot trauma
• amputation
• dislocation
• complete fracture
• incomplete (green-stick) fracture
• comminuted (splinter) fracture
• compound fracture
• pseudo-arthrothis (false-joint)
• Colles fracture
• Parry fracture
• depressed fracture
• woven bone
• callus
• taphonomic process
• antemortem
• perimortem
• postmortem
• diaphysis

GENERAL INSTRUCTIONS

• Carefully handle the bones laid out in the lab, being sure to keep the bones on bubble wrap with their provenience labels.

• Hand lenses are available for low magnification examination of the skeletal material.  Use a strong light or sunlight.

• Record your responses to the questions on the answer sheet provided.  Pencil is mandatory for recording your answers.

• Use reference books in the lab as needed.

• The lab is due at the beginning of class on Thursday, April 24.  Late labs will not be accepted.
  

SKELETAL TRAUMAS

TYPES OF SKELETAL TRAUMAS

A variety of skeletal traumas, or damage to bones as a result of the application of force via accident or an instrument or weapon, may be manifested in forensic cases and may be used in developing a biological profile.  Skeletal traumas include bone fractures, blunt-force traumas, sharp-force traumas, gunshot traumas, burning, amputation, and dislocation.  Each of these skeletal traumas was discussed and illustrated in class.  In this lab we'll examine and assess bone fractures and sharp-force traumas.

Bone fractures include a variety of breaks to bones that result from the application of unusual forces to bone.  Depending on the type and magnitude of force and the skeletal effects, bone fractures are divided into at least eight types (Sciulli 1991).

• Complete fractures are angular, separated bone breaks that result from significant angular or oblique forces.

• Incomplete or green-stick fractures are angular bone breaks that do not separate. They result from less significant angular or oblique forces.

• Comminuted or splinter fractures involve bone fragmentation resulting from the application of perpendicular forces to the bone.

• Compound fractures are bone breaks in which the fractured bone or fragments pierce the skin, potentially resulting in infection. They result from angular or perpendicular forces.

• Pseudo-arthrothis or false joints are bone breaks in which the bones are separated but too far apart to rejoin during the healing process.

• Colles fractures are usually incomplete fractures of the distal ulna, distal radius, or clavicle. They result from trying to catch oneself with one's hands when falling.

• Parry fractures are complete or incomplete fractures of the ulna and radius diaphyses that result from self defense.

• Depressed fractures are circular fractures of the skull (or other flat bones) that result from armed attached with blunt objects.

The image below shows a healed bone fracture that was likely a complete fracture.

Sharp-force traumas are incised wounds and stab wounds resulting from attacks or accidents with knives, swords, axes, and other sharp implements.  Such injuries cause bone cracks, incisions, scratches, gouges, piercing, and fragmentation of bone. The size and shape of sharp-force traumas provide clues to the instrument that caused the damage, the direction of the attack or accident, and the nature of the events leading to an individual's death (Rhine 1998, Sciulli 1991).

Sharp-force traumas resulting from attacks with metal objects and stone objects must be distinguished from skeletal modifications from postmortem taphonomic processes like rodent gnawing, carnivore gnawing, and trampling.  Metal and stone objects leave single, V-shaped incisions that have straight parallel edges. Such traumas could be antemortem, perimortem, or postmortem. Rodent gnawing leaves paired, U-shaped parallel incisions on bones (Sciulli 1991), while carnivore gnawing leaves single, U-shaped incisions or "channels" on bones.  While cut marks and incisions tend to be found on the highest relief parts of bones, rodent and carnivore gnawing marks may be found in bone depressions as well.  We will examine rodent gnawing and carnivore gnawing in Lab 12.

The images below illustrate incisions resulting from sharp-force trauma with a stone instrument and rodent gnawing that resembles sharp-force incision traumas.

It is important to assess when skeletal traumas occurred - before death, at the time of death, or after death. Skeletal traumas occurring before death may be useful in identifying an individual's identity if those traumas were documented in writing or, better yet, x-rays by physicians or if they required medical hardware to repair.  Skeletal traumas incurred at the time of death may be potential causes of death or may be used to reconstruct the events of the crime.  Skeletal traumas incurred after death are usually the result of taphonomic processes or improper retrieval and transport of skeletal remains (Rhine 1998, Pickering and Bachman 1997).

Skeletal traumas that were incurred before death are called antemortem traumas.  They are distinguished by nondifferential weathering and more-or-less even discoloration of the trauma site as well as evidence of healing in the form of calluses or bone remodeling (Rhine 1998).

Perimortem traumas are those incurred at the time of death.  The effected bones will show no evidence of healing and will be nondifferentially weathered and discolored.  Radiating fractures are often present (Rhine 1998).  Fractures often spiral around the diaphysis.

Skeletal traumas incurred after death are called postmortem traumas. The effected bones will show no evidence of healing and will be differentially weathered and discolored. The trauma edges will be fresher and sharper than those resulting from perimortem traumas.  Longitudinal fractures may be present (Rhine 1998).  Fractures are often perpendicular to the diaphysis.
 

ASSIGNMENT

Record all answers neatly in pencil on the answer sheet. Metric answers should be reported to the level of accuracy (tenths place, ones place, etc.) specified for those questions on the answer sheet. Metric answers, if appropriate, must have units.

Examine the skeletal specimens and casts, carefully handling the bones. For each specimen you will answer questions related to (1) the skeletal element (e.g., bone name, side, end); (2) the nature of the trauma (e.g., length, diameter, color); (3) the specific type of trauma; and (4) the timing of the trauma (e.g., antemortem, perimortem, postmortem).

Bass, W. M.
1987 Human Osteology: A Laboratory and Field Manual (3rd ed.). Missouri Archaeological Society, Columbia.

Byers, Stephen N.
2005 Introduction to Forensic Anthropology: A Textbook. Allyn and Bacon, Boston.

Byers, Stephen N. and Susan M.T. Myster
2005 Forensic Anthropology Laboratory Manual. Allyn and Bacon, Boston.

France, D. L. 
2003 Lab Manual and Workbook for Physical Anthropology (5t ed.). West/Wadsworth, Belmont, CA.

Pickering, R.B. and D.C. Bachman
1997 The Use of Forensic Anthropology. CRC Press, Boca Raton.

Rhine, S. R.
1998 Bone Voyage: A Journey in Forensic Anthropology. University of New Mexico Press, Albuquerque.

Sciulli, P.
1991 Class notes, Biocultural Adaptations in Prehistory. The Ohio State University, Columbus.

Spitz, W. U. (editor)
1993  Spitz and Fisher's Medicolegal Investigation of Death (3rd ed.).  Charles C. Thomas, Springfield, Illinois.

White, T. D.
1991 Human Osteology. Academic Press, San Diego.