Sex Estimation of the Human Skeleton

History, Methods, and Emerging Techniques

Alexandra R. Klales

• Publisher: Academic Press
• Year: 2020
• Print ISBN: 9780128157671
• eBook ISBN: 9780128157688
• Topic: Medicine
• Subtopic: Orthopedics

Sex Estimation of the Human Skeleton is a comprehensive work on the theory, methods, and current issues for sexing human skeletal remains. This work provides practitioners a starting point for research and practice on sex estimation to assist with the identification and analysis of human remains. It contains a collection of the latest scientific research, using metric and morphological methods, and contains case studies, where relevant, to highlight methodological application to real cases. This volume presents a truly comprehensive representation of the current state of sex estimation while also detailing the history and how we got to this point.Divided into three main sections, this reference text first provides an introduction to the book and to sex estimation overall, including a history, practitioner preferences, and a deeper understanding of biological sex. The second section addresses the main methodological areas used to estimate sex, including metric and morphological methods, statistical applications, and software. Each chapter topic provides a review of older techniques and emphasizes the latest research and methodological improvements. Chapters are written by practicing physical anthropologists and also include their latest research on the topics, as well as relevant case studies. The third section addresses current considerations and future directions for sex estimation in forensic and bioarchaeological contexts, including DNA, secular change, and medical imaging Sex Estimation of the Human Skeleton is a one-of-a-kind resource for those involved in estimating the sex of human skeletal remains.- Provides the first comprehensive text reference on sex estimation, with historical perspectives and current best practices- Contains real case studies to underscore key estimation concepts- Demonstrates the changing role of technology in sex estimation

Part 1

Introduction to sex estimation

Chapter 1

A history of sex estimation of human skeletal remains

Alexandra R. Klales; Holly Long; Cassidy Willsey Forensic Anthropology Program, Department of Sociology and Anthropology, Washburn University, Topeka, KS, United States

Abstract

This chapter traces the origins of how, first, the sexes were differentiated skeletally and then, later, how sex has been estimated and interpreted from the human skeleton. This chapter includes cultural accounts and scientific research on sex differences dating back to biblical times up until the mid-1950s. An emphasis is placed on how our knowledge grew from early anatomical studies to research focusing specifically on modern skeletal collections.

Keywords

Sex estimation; Forensic anthropology; Biological profile; Bioarchaeology; Methods

Introduction

Our understanding of the skeletal differences between males and females grew from an appreciation of human anatomy and later with a specific emphasis on human osteology. The historical review below focuses on advancements in skeletal anatomy and biology through the lens of sex estimation. Our history begins with religious, biblical, and early philosophical explanations and then moves to more scientific approaches with anatomy, human osteology, forensic applications, and then finally research and methodology development. This comprehensive history extends up to the mid-20th century (around the 1950s), as much of what has been done since then has already been extensively covered elsewhere (cf. Moore, 2013) and is also covered in part within the history sections of chapters in this volume.

History of human skeletal sex estimation

Differences between the sexes have “puzzled humanity since ancient times- not only within a scientific context, but also within a social context” (Stévant, Papaioannou, & Nef, 2018, p. 8). The review presented below speaks about sex differences from a binary perspective (male and female) based on historical works, but the authors recognize that both gender and biological sex exist along a spectrum (see Chapter 4 in this volume for a more in-depth discussion of sex, gender, and terminology from both a sociocultural and a biological perspective).

Prior to our understanding of human anatomy and osteology, many religious and philosophical explanations existed for the differences between females and males. For example, Greek philosopher Aristotle (335 BC) based sex differences on earthly elements: males had more fire and females had more water and that temperature during intercourse determined the sex of the offspring (Gardiner & Swain, 2015; Stévant et al., 2018). This notion of environmental sex determination in humans remained popular and persisted until the turn of the 20th century (Gardiner & Swain, 2015). Christian biblical accounts explain the “design” of females when God created Eve by taking a rib from Adam, leading to the long-held erroneous belief that males have one fewer rib than females. Even Earnest Hooton, one of the most influential biological anthropologists, theorized that females had fewer ribs to accommodate an expanded uterus during pregnancy (Hooton, 1946). These beliefs have carried through Western medicine for years and are still sometimes perpetuated today despite scientific inquiry and affirmation proving otherwise.

Human anatomy

The first recorded account of what we would today call human internal anatomy comes from early ancient Egyptian texts (3000–2500 BC), quite unsurprisingly tied to both natural and artificial mummification, the latter of which required extensive anatomical knowledge (Persaud, 2014). There was a distinction made in the burial practices between the sexes in ancient Egypt, but there is no mention of known skeletal differences. Later, more evidence of anatomical studies appeared in India beginning in 1500 BC with the Vedas text (Zysk, 1986). An understanding of skeletal anatomy was rather limited likely due, in part, to the restrictions and cultural stigma associated with anatomical dissections at this time. The first record of the study of skeletal elements occurred around 600 BC—thousands of years after the first recorded study of human anatomy—by a physician named Susutra who dissected children in an attempt to better understand the body. At the time, any deceased individual over the age of two was burned following Hindu practice; therefore, he was restricted to young subadults. His records describe the body as having 300 bones, likely due to studying children with unfused epiphyses (Persaud, 2014; Zysk, 1986). Later Hippocrates (420 BC), known for his contribution to medicine and the creation of the Hippocratic Oath, wrote several treatises on medicine, including knowledge of human skeletal form. In his chapter “On Injuries of the Head,” he noted human variation in sutures (Adams, 1886). Osteological knowledge was extremely limited at this time, which in turn limited the knowledge of skeletal differences between the sexes.

Human osteology

Galen's De Ossibus ad Tirones (translated as On Bones for Beginners) (AD 180) was the first published work dedicated entirely to human osteology. He noted differences between males and females in the neck of the femur, indicating females angled less than males (Singer, 1956). He also noted a harder, more articulated skeleton in fetuses of males versus females, with males developing more quickly (Connell, 2000). Although some knowledge of osteology and perceived sex differences appeared in medical and anatomical texts, it was not until the 13th century that a record of osteological applications to differentiating the sexes from the skeleton was found in The Washing Away of Wrongs by Song Tz’u (1247). This text is widely considered the earliest record of forensic sciences. The work includes crude methods for differentiating males and females based on coloration of the remains, with male bones being white and female bones being darker (Tz’u 1247; translated by McKnight, 1981). Tz’u also believed there were sex differences in the number of cranial bones with males having eight, whereas females had only six due to a lack of “a vertical [suture] running down the hairline in the back” (McKnight, 1981, p. 34). Such a divergence in bone quantity was attributed to the importance of numerology in ancient China (McKnight, 1981). Though most of these noted sex differences have since been disproven due to the great variety of factors that can cause discoloration to the bones or fused sutures, these early works were revolutionary in their specific focus on human osteology.

Describing and understanding sex differences

We begin to see the first studies of sex differences on the skeletal form during the 16th century; however, anatomists of this time said very little on the subject as their primary focus was not on questions of sex differences (Schiebinger, 1986). The anatomists Vesalius (1543), in De Humani Corporis Fabrica (On the Fabric of the Human Body), and Bauhin and de Bry (1605), in Theatrum Anatomicum, were among the first to distinctly illustrate and/or describe the female skeleton in comparison to the male skeleton, implying that there were enough differences between the two to warrant separate representations. In each case, females were contrasted against the male form, likely indicating a level of perceived inferiority of women that was common at the time. Schiebinger (1986, p. 42) suggests that “defining sex differences in every bone … became a research priority” in ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• About the contributors
• About the editor
• Acknowledgments
• Introduction to sex estimation and this volume
• Part 1: Introduction to sex estimation
• Part 2: Methods for sex estimation
• Part 3: Current considerations
• Index