Determining Sex from Skeletal Remains: Key Anatomical Indicators

Forensic Sex Estimation from the Skeleton

Sex estimation relies on sexually dimorphic features. Accuracy: pelvis 95%, skull 85-90%, long bones 80-85%. Best practice: multi-indicator approach.

Pelvis (Most Reliable)

Feature	Female	Male
Subpubic angle	>90° (wide)	<90° (narrow)
Sciatic notch	Wide, U-shaped	Narrow, V-shaped
Ventral arc	Present	Absent
Preauricular sulcus	Often present	Rare
Sacrum	Shorter, wider, less curved	Longer, narrower, more curved
Acetabulum	Smaller, anterior	Larger, central

Phenice method (ventral arc, subpubic concavity, medial ischiopubic ridge): 96% accuracy.

Skull

Feature	Female	Male
Glabella/supraorbital ridge	Smooth, minimal	Prominent, rugged
Mastoid process	Small, pointed	Large, blunt
Nuchal crest	Smooth	Rugged, hooked
Mental eminence	Rounded, vertical	Square, projecting
Orbit shape	Round, sharp margins	Rectangular, blunt margins
Overall size/robusticity	Smaller, gracile	Larger, robust

Long Bones (Metric)

• Discriminant function analysis: femur head diameter, humeral head, femoral bicondylar width
• Population-specific formulas essential (secular trends, ancestry)
• Stature estimation also sex-dependent

Critical Caveats

• Ancestry matters: Dimorphism magnitude varies by population
• Age: Prepubertal skeletons not reliably sexed; elderly changes obscure features
• Individual variation: Overlap exists; probabilistic, not binary
• Fragmentary remains: Reduces accuracy
• DNA analysis: Definitive (amelogenin, SRY); gold standard when available

Best Practice Protocol

1. Assess preservation and completeness
2. Score pelvic traits (primary)
3. Score cranial traits (secondary)
4. Apply metric discriminant functions if long bones intact
5. Integrate findings; assign probability (male/female/indeterminate)
6. Document uncertainty

Sex estimation is a probability statement, not a definitive fact. Context and multiple lines of evidence are essential.