Cortical Bone
Definition
The dense outer shell of long bones, also called compact bone. Porosity is less than 10 percent. High mineral density, slow water diffusion, and restricted microbial access make cortical bone the preferred sampling site for forensic DNA extraction from degraded remains.
- Also called
- Compact bone
- Location
- Dense outer shell of long bones
- Porosity
- Less than 10 percent
- Forensic use
- Preferred DNA extraction site for degraded remains
Common questions
Why is cortical bone preferred over cancellous (spongy) bone for DNA extraction from degraded remains?+
Its low porosity slows water diffusion and restricts microbial access compared to the more porous cancellous bone, which better protects DNA from hydrolytic damage and microbial degradation over time.
Does the source bone element matter, or is any piece of cortical bone equally good?+
Element and location matter; weight-bearing long bones such as the femur are commonly favoured because their cortical wall is thickest and best protected, though the specific choice depends on what remains are available and their preservation state.
Related terms
- Hydroxyapatite
- The calcium phosphate mineral (Ca10(PO4)6(OH)2) that constitutes approximately 70 percent of bone dry weight. Its crystals bind to DNA fragments electrostatically, slowing...
- Inhibitor Removal
- Laboratory steps applied to degraded bone before PCR amplification. Collagen hydrolysis products, humic acids, and heavy metals in aged bone inhibit DNA...
- Osteon (Haversian System)
- The basic structural unit of compact cortical bone: a central Haversian canal surrounded by concentric lamellae of mineralised collagen. Osteon diameter and...
- Stable Isotope Analysis
- A technique that measures the ratio of stable (non-radioactive) isotopes of elements such as strontium, oxygen, and carbon in a biological sample....
- Trabecular Bone
- The spongy inner lattice of bone, found at epiphyses and in flat bones. Porosity of 50 to 90 percent allows rapid water...