Kerley Method
Definition
A histological age estimation method published by Ellis Kerley in 1965, based on counting secondary osteons, osteon fragments, circumferential lamellar bone, and non-Haversian canals in 100x ground sections of femoral, tibial, or fibular cortex. Standard error approximately plus or minus 8-10 years on the femur.
- Author
- Ellis Kerley
- Published
- 1965
- Basis
- Osteon counts in 100x ground cortical sections
- Bones used
- Femur, tibia or fibula
- Standard error
- About plus or minus 8 to 10 years on the femur
Common questions
Why does the Kerley method require a destructive bone section?+
Counting secondary osteons, fragments and non-Haversian canals accurately requires a thin ground cross-section viewed under magnification, which cannot be assessed from an intact bone surface, making it a destructive technique used mainly when other age indicators are unavailable or inconclusive.
How has the original Kerley method been improved since 1965?+
Later researchers such as Ahlqvist and Damsten revised the counting fields and formulas to correct for inter-observer variation and to extend applicability across different populations, since Kerley's original reference sample was limited in size and demographic range.
Related terms
- Cortical (Compact) Bone
- The dense outer shell of long bones and the tables of flat bones. Approximately 80% of skeletal mass. High mineral density (65-70%...
- Epiphyseal Growth Plate (Physis)
- The cartilaginous zone between the epiphysis and metaphysis where endochondral ossification occurs during growth. Closes (fuses) at puberty under the influence of...
- Haversian System (Secondary Osteon)
- The basic structural unit of mature cortical bone: a cylinder of 4-20 concentric lamellar rings around a central Haversian canal carrying blood...
- Interstitial Lamellae
- The angular remnants of older osteons left behind after a BMU has partially resorbed them. Their relative area decreases with age as...
- Lacuna
- A small lens-shaped cavity within bone lamellae that houses an osteocyte cell body. Lacunae are connected by canaliculi radiating toward the Haversian...
- Osteoclast
- The large, multinucleated bone-resorbing cell responsible for excavating the resorption tunnel in a BMU. Activated by the RANKL/OPG cytokine axis. Creates the...
- Plexiform Bone
- A microstructural pattern found in the cortical bone of large rapid-growth mammals (bovids, horses, deer) characterised by alternating layers of woven bone...
- Trabecular (Cancellous) Bone
- The porous, lattice-like interior bone occupying epiphyses, metaphyses, and flat bones. High surface area and metabolic activity but rapidly lost in taphonomic...
- Wolff's Law
- The principle that bone is deposited and resorbed in response to mechanical loading history. Cortical thickness and trabecular orientation follow principal stress...