Differences Between Male and Female Pelvis

(Source: P C Dikshit Textbook of Forensic Medicine and Toxicology, Table 6.10 & 6.11)

The pelvis is the most reliable bone for sex determination in skeletal remains, with an accuracy of ~95%. The differences arise due to the functional demands of childbearing in females.

Comparison - Male and Female Pelvis

Female pelvis (left) vs Male pelvis (right)

Feature	Male Pelvis	Female Pelvis
General framework	Deep, funnel-shaped; massive and rough	Shallow, bowl-shaped; less massive and smooth
True pelvis	Narrow, deep, funnel-shaped	Wide and shallow
Pelvic brim	Heart-shaped	Circular / oval
Pelvic outlet	Smaller	Larger
Ilium	Curve more prominent, more sloped with less rounded margins	Curve less prominent, less sloped with more rounded margins
Iliac crest	More prominent	Less prominent
Anterior superior iliac spine (ASIS)	Not widely separated	Widely separated
Pre-auricular sulcus	Not prominent; narrow and shallow	Prominent, broad and deep
Acetabulum	Wide and deep; ~52 mm diameter	Small and narrow; ~46 mm diameter
Symphysis pubis	Higher and bigger in depth, narrow in width; margins of pubic arch are everted; no parturition pits	Lower, wider and rounded; margins are not everted; parturition pits present on dorsal border (evidence of childbearing)
Subpubic angle	70-75° (acute); subpubic arch is V-shaped	~90° or more; subpubic arch is U-shaped
Greater sciatic notch	Smaller, deeper, narrower; less than a right angle	Wider, larger, shallower; forms approximately a right angle
Sciatic notch index (Width/Depth)	4-5	5-6
Obturator foramen	Large, oval-shaped with base upwards	Small, triangular with apex directed forwards
Ischial tuberosity	More or less inverted	Everted (laterally turned out)
Pubis (body)	Narrow and triangular	Broad and square
Pubis (ramus)	Continuation of body	Narrow appearance
Pelvic index (AP/Transverse diameter x100)	More	Less
Kell index (Acetabulum SA / Ilium SA x100)	More	Less
Ischiopubic index (Ischial length/Pubic length x100)	73-94	91-115

Differences in the Sacrum (Table 6.11)

Female pelvis

Male pelvis

Feature	Male Sacrum	Female Sacrum
General	Long and narrow; sacral promontory well-marked; anterior curvature equally distributed along its length	Shorter and wider; less prominent sacral promontory; upper half straight, lower half sharply curved
Sacroiliac articular surface	Large; extends up to 2.5-3 vertebral bodies	Small; extends up to 2-2.5 vertebral bodies
Coccyx	Less movable	More movable
Sacral index (Breadth/Anterior length x100)	112	116

Key Memory Points (Exam Focus)

Subpubic angle is the single most reliable feature - V-shaped in male, U-shaped in female
Greater sciatic notch - wide and shallow in female (roughly right angle), narrow and deep in male
Parturition pits - present only in females (on dorsal surface of pubic symphysis, evidence of past childbirth)
Pre-auricular sulcus - well-marked in females, used for sex determination
Overall shape - female pelvis is wide/bowl-shaped (for parturition); male is deep/funnel-shaped (for locomotion)
Pelvic brim - circular in female, heart-shaped in male
Accuracy of sex determination from pelvis alone = ~95%

Clinical Significance

These differences are directly relevant to obstetrics - the wider, shallower female pelvis accommodates the fetal head during labour
In forensic medicine, the pelvis is the gold-standard bone for skeletal sex determination, even from fragmentary remains
The ischiopubic index (91-115 in females vs. 73-94 in males) is a useful quantitative parameter
Parturition pits additionally confirm a female who has given birth

(Source: P C Dikshit Textbook of Forensic Medicine and Toxicology, pp. 83-84)

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