Location
Philadelphia, PA
Start Date
17-4-2026 1:30 PM
End Date
17-4-2026 2:30 PM
Description
Introduction
Bone health and structural variation are multifactorial. Population, environment, age, diet, and health influence the overall functional morphology of bone and its response to stressors. Reduced cortical porosity, trabecular thinning, and low bone mass are common indicators of age-related and pathological changes, affecting a significant portion of the population. Because of this, bones encountered in medicolegal investigations often differ from what is considered “normal.” The structural integrity of bone needs to be considered because density influences mechanical strength and response to external forces.
In criminal dismemberment cases, forensic scientists analyze saw marks to identify tool class and reconstruct events. While a large body of literature examines saw mark characteristics, prior research has paid little attention to overall bone health. This study evaluates the effects of variation in bone density on saw mark formation in human femora, testing the hypothesis that variation in relative bone density produces measurable differences in saw mark morphology.
Methods
Fourteen femora from seven anatomical donors and an additional eight dried femora were obtained through the PCOM Human Anatomy Laboratory. Specimens with surgical hardware or visible metastasis were excluded. All femora were manually defleshed. Relative bone density was assessed using an Archimedes-based approach, calculating the difference between dry mass and submerged weight as a density proxy, standardized for femoral length.
Saw marks were produced using a corded electric compound miter saw with a 7.25-inch, 24-tooth blade. Ten successive cuts were made along the shaft at forty-five degrees by a single operator. Specimens were imaged under fixed stereoscopic parameters, and key features were measured in Fiji using calibrated line regions of interest. Density proxy values were standardized for femoral length using ANCOVA in IBM SPSS Statistics. Multivariate analysis evaluated variation in saw mark characteristics relative to the density proxy.
Results
Density proxy values varied meaningfully across specimens, indicating measurable variation in relative bone density. Preliminary testing and imaging of representative samples indicate that specimens with lower density proxy values produced saw marks with distinguishable morphological differences compared to higher-density specimens, including variation in kerf-wall definition and floor texture. These findings suggest that relative bone density influences the expression of saw marks in human femora.
Discussion
Bone density contributes to variation in saw mark morphology beyond what can be attributed to tool class alone. Because reduced bone density is prevalent in aging populations and among individuals with compromised health, forensic interpretations that do not account for skeletal variation risk misclassifying tool marks. Incorporating bone health into saw mark analysis frameworks may improve the reliability of medicolegal interpretations and strengthen forensic guidelines for skeletal trauma analysis. Additionally, understanding how bone density influences the mechanical response of cortical bone to saw forces may inform orthopedic surgical planning, particularly in procedures involving osteotomy or prosthetic implantation in patients with compromised skeletal integrity.
Embargo Period
6-3-2026
Included in
The Effects of Bone Health and Variation on Saw Mark Signatures
Philadelphia, PA
Introduction
Bone health and structural variation are multifactorial. Population, environment, age, diet, and health influence the overall functional morphology of bone and its response to stressors. Reduced cortical porosity, trabecular thinning, and low bone mass are common indicators of age-related and pathological changes, affecting a significant portion of the population. Because of this, bones encountered in medicolegal investigations often differ from what is considered “normal.” The structural integrity of bone needs to be considered because density influences mechanical strength and response to external forces.
In criminal dismemberment cases, forensic scientists analyze saw marks to identify tool class and reconstruct events. While a large body of literature examines saw mark characteristics, prior research has paid little attention to overall bone health. This study evaluates the effects of variation in bone density on saw mark formation in human femora, testing the hypothesis that variation in relative bone density produces measurable differences in saw mark morphology.
Methods
Fourteen femora from seven anatomical donors and an additional eight dried femora were obtained through the PCOM Human Anatomy Laboratory. Specimens with surgical hardware or visible metastasis were excluded. All femora were manually defleshed. Relative bone density was assessed using an Archimedes-based approach, calculating the difference between dry mass and submerged weight as a density proxy, standardized for femoral length.
Saw marks were produced using a corded electric compound miter saw with a 7.25-inch, 24-tooth blade. Ten successive cuts were made along the shaft at forty-five degrees by a single operator. Specimens were imaged under fixed stereoscopic parameters, and key features were measured in Fiji using calibrated line regions of interest. Density proxy values were standardized for femoral length using ANCOVA in IBM SPSS Statistics. Multivariate analysis evaluated variation in saw mark characteristics relative to the density proxy.
Results
Density proxy values varied meaningfully across specimens, indicating measurable variation in relative bone density. Preliminary testing and imaging of representative samples indicate that specimens with lower density proxy values produced saw marks with distinguishable morphological differences compared to higher-density specimens, including variation in kerf-wall definition and floor texture. These findings suggest that relative bone density influences the expression of saw marks in human femora.
Discussion
Bone density contributes to variation in saw mark morphology beyond what can be attributed to tool class alone. Because reduced bone density is prevalent in aging populations and among individuals with compromised health, forensic interpretations that do not account for skeletal variation risk misclassifying tool marks. Incorporating bone health into saw mark analysis frameworks may improve the reliability of medicolegal interpretations and strengthen forensic guidelines for skeletal trauma analysis. Additionally, understanding how bone density influences the mechanical response of cortical bone to saw forces may inform orthopedic surgical planning, particularly in procedures involving osteotomy or prosthetic implantation in patients with compromised skeletal integrity.