SEX DETERMINATION FROM
HUMAN SKELETAL REMAINS
{SKULL , PELVIS , STERNUM}
As humans, we have three basic
racial groups. These groups are
Caucasoid, Mongoloid, and Negroid.
With the addition of inter-breeding,
many other subgroups can be found.
Each group possesses unique
skeletal characteristics which allow
us to "race" the remains of a person.
In addition to race, we can also
estimate age, stature, and sex.
Using Bones for Identification
It consists of a five phase procedure:
1) A general description and confirmation of the human
origins of the material.
2) The estimation and segregation of the minimum
number of individuals.
3) The determination of sex.
4) The estimation of age.
5) The estimation of stature.
Introduction
Skeleton is an excellent material in living and nonliving population for genetic, anthropological,
odontologic and forensic investigations. Skull and
bone features vary from male to female and
differentiation is usually based on the male
features that are typically more pronounced and
marked than female features.
The human skeleton consists of both fused
and individual bone. Fused bones include
those of the pelvis and the cranium.
At birth a newborn baby has approximately
300 bones, whereas on average an adult
human has 206 bones . The difference comes
from a number of small bones that fuse
together during growth, such as the sacrum
and coccyx of the vertebral column.
The determination of sex by
examination of the skeleton is
based upon the appearances
of:
1. Pelvis (innominates +
sacrum )
2. Skull (cranium + mandible )
3. Long bones (Humerus ,
Femur )
4. Sternum
5. Scapula , metacarpal bones
Krongman ranks accuracy of sex
determination using the pelvis at
95% , the skull at 90%, the pelvis
and skull at 98% and long bones at
80%.
SEXUAL DIMORPHISM
Differences between men and women
include all the features related to
reproductive role, notably the endocrine
(hormonal) systems and their physical,
psychological and behavioral effects.
SEXUAL DIMORPHISM –
BASIC PRINCIPLES
The evaluation of sexual dimorphism in skeleton
is generally based on two factors:
1. Size difference
2. Function related differences.
Determination of sex is based on two methodological
approaches:
1.Morphological (based on Shape ) Adult males
and females differ in both general size and
shape, and this variation is reflected in the
skeletal anatomy.
2. Osteometric (based on bone dimensions)
Males longer or larger than females.
The skull is a bony structure
which serves as the general
framework for the head. The
skull supports the structures
of the face and protects the
head against injury.
The skull can be
subdivided into two parts:
the cranium and the
mandible.
SKULL
The features that indicate sex are :
1.General appearance
2.Supra orbital ridges
3.Orbits
4.Glabella
5.Zygomatic arches
6.Mastoid processes
7.External occipital protuberance
8.Mandible
9.Palate
MALE
FEMALE
When compared, the female skull
appears smaller and more gracile. The
male skull is usually larger and more
rugged.
Supraorbital ridges
This is the region directly above
the orbit and nose, or the "brow
ridge“.
Less pronounced=female
More pronounced=male
ORBITS
SQUARISH WITH
ROUNDISH MARGINS
MALE
ROUNDISH WITH SHARP
MARGINS
FEMALE
The frontal bone (forehead) of
males tends to be slanted back and
on females it tends to be more
rounded
GLABELLA
WELL DEVELOPED
MALE
ILL DEVELOPED
FEMALE
Zygomatic arches
In females, the zygomatic arch is less pronounced, and tends
to not extend posteriorly beyond the external auditory
meatus.
In males, the zygomatic arch is more pronounced or
robust, and tends to extend posteriorly beyond the external
auditory meatus.
MASTOID PROCESSES
The mastoid processes are located on the inferior
portion of the temporal bone, just posterior to the
external auditory meatus.
EXTERNAL OCCIPITAL PROTUBERANCE
MALE
FEMALE
The mandible together with the maxilla, the
largest and strongest bone of the face . It forms
the lower jaw and holds the lower teeth in
place.
Chin (anterior mandible)
The male mandible
tends to have a
“square” shape.
Mandible of female
tends to have a
pointed chin.
RAMUS (rear of the mandible)
Mandible in the
male is closer to a
right angle than
the female. In the
female, the ramus
is an obtuse angle
to the lower jaw
bone, i.e., greater
than 90 degrees.
The ramus in the
male is wider and
larger.
MALE
FEMALE
PALATE
LARGER,WIDER AND
BROADER
MALE
SMALLER AND
NARROWER
FEMALE
Slide 27: Using the previous slides and pictures, identify
whether the following skull parts are from a male or female?
1. Mandible
3. Frontal Bone

2. External occipital protuberance
PELVIS
The pelvis comprises the two
innominates and the sacrum.
HIP BONE
The best indicator of sex on
the adult skeleton is the
shape of the pubic bone of
the pelvis.
The hip bone (or innominate bone) is a large,
flattened, irregularly shaped bone.
Together with the sacrum and coccyx, it
comprises the pelvis.
Components
It consists of three parts, the ilium, ischium,
and pubis, which are distinct from each other in
the young subject, but are fused in the adult.
Sex Determination from Pelvic Morphology
The pelvic girdle is the most sexually dimorphic
region of the skeleton, and it can be used to
determine sex with a high degree of accuracy.
The sexual dimorphism of the pelvis is primarily
the result of reproductive mechanics, and is not
readily apparent until adolescence.
Sex differentiation in the human pelvis
1. Overall appearance between the two pelvic regions .The male pelvis is
larger and more robust than the female pelvis.
2. The size of the opening between the hips (A). The female skeleton
requires this additional room for birthing.
3. The hips in the male (B) are more vertical than the female's.
4. At the rear of the pelvis is the coccyx (C), the male coccyx is larger than
the female's.
5. The angle at the front of hips (D), where both sides join (pubic symphysis)
is an obtuse angle in the female, and closer to 90 degrees in the male.
The female obtuse angle is in-line with the broader birthing canal.
PELVIS
Five features in innominate that indicate sex in
pubic region are:
(1) width of sciatic notch (inferior ilium)
(2) subpubic angle (concavity)
(3) ventral arc (on the pubis, near the
symphysis, ventral)
(4) ischio-pubic ramus (bone connecting
pubis and ischium)
(5) acetabulum diameter
(lateral innominate)
SCIATIC NOTCH
SMALL AND DEEP
MALE
WIDER AND SHALLOWER
FEMALE
SCIATIC NOTCH
Generally, the sciatic notch
tends to be wider in the
female and narrower in the
male.
SUBPUBIC
ANGLE
LESS AND “V” SHAPED
MALE
WIDE AND TEND TO “U”
SHAPED
FEMALE
The subpubic angle is much wider in females than in
males, typically more that 90 degrees and less than 90
degrees, respectively.
It is the curved ridge of bone on anterior surface of
the pubic bone.
It is common in females and almost never seen in
males.
PELVIC INLET
The pelvic inlet
is the space
you see when
both
innominates
and sacrum are
articulated.
The space in the middle of the pelvic bone (the
pelvic inlet) is larger in women to facilitate
birthing.
The sacrum is a large, triangular bone at the
base of the spine and at the upper and back
part of the pelvic cavity.
The sacrum articulates with four bones:
•the last lumbar vertebra above
•the coccyx below
•the hip bone on either side
Sexual dimorphism
The sacrum is
noticeably sexually
dimorphic .
In the female the
sacrum is shorter and
wider than in the male.
The bone is also
directed more obliquely
backward; this increases
the size of the pelvic
cavity.
Straighter in males &
curved in females.
MALE
FEMALE
Slide 45: Using the previous slides discussing the pelvis,
determine whether each of the pelvic bones pictured
corresponds to a male or female.
1. Subpubic angle
3. Sacrum
2. Pelvic Inlet
4. Sciatic
Notch
The sternum is an
elongated, flattened bone,
forming the middle portion
of the anterior wall of the
thorax. Its upper end
supports the clavicles and
its margins articulate with
the cartilages of the first
seven pairs of ribs.
It consists of three parts,
from above downward:
•Manubrium
•Body of sternum
•Xiphoid process
<125 mm = female
>155 mm = male
These figures are from Bass
• The Essentials of Forensic Medicine
By : Cyril John Polson , D.J.Gee , Bernard Knight
• Encyclopedia of Forensic Sciences
• Clinical Anatomy for Medical Students
By : Richard S . Snell
• Wikipedia
• Personal Identification from skeleton or its remains
By : G.S. Kaler & N.A. Butt