Secondary Ossification Centre
Definition
An epiphysis: a discrete bony island that forms postnatally at the articular end of a long bone, separated from the diaphysis by the epiphyseal cartilage plate. Fusion of the epiphysis to the diaphysis terminates longitudinal bone growth at that site.
- Also called
- Epiphysis
- Location
- Articular end of a long bone
- Separated by
- Epiphyseal cartilage growth plate
- Fusion effect
- Terminates longitudinal growth at that site
Common questions
Why are secondary ossification centres useful for skeletal age estimation?+
Their appearance and later fusion to the diaphysis follow a reasonably predictable timing through childhood and adolescence, so assessing which centres are present, fusing, or fused helps bracket a subadult's age.
Do all long bones have the same number of secondary ossification centres?+
No, the number and location vary by bone; some long bones have centres at both ends while certain hand and foot bones have only one, and that pattern feeds directly into age-estimation standards.
What if a secondary ossification centre fuses asymmetrically or late?+
Asymmetric or delayed fusion can reflect normal individual variation, nutritional or hormonal factors, or occasionally pathology, so anthropologists interpret timing against population reference data rather than a fixed age.
Related terms
- Appendicular Skeleton
- The 126-bone system of the human limbs and their girdles: the pectoral girdle (4), upper limbs (60), pelvic girdle (2 os coxae),...
- Axial Skeleton
- The 80-bone central structural column of the human skeleton: the skull (29 bones), the vertebral column (26 bones including sacrum and coccyx),...
- Endochondral Ossification
- The process by which bone replaces a cartilage precursor. All long bones, the vertebrae, the ribs, and the cranial base form by...
- Epiphyseal Fusion
- The obliteration of the cartilaginous growth plate and bony union of the epiphysis with the diaphysis. Fusion sequence and timing form the...
- Intramembranous Ossification
- The process by which bone forms directly from a mesenchymal membrane without a cartilage intermediate. Produces the flat bones of the skull...
- Medial Clavicle Epiphysis
- The last secondary ossification centre to fuse in the human skeleton, completing at 21 to 30 years depending on sex and population....
- Mukherjee 1955 Dataset
- Sub-adult skeletal age reference data published by P. K. Mukherjee and colleagues from AIIMS New Delhi, demonstrating that several epiphyses fuse 1...
- Primary Ossification Centre
- The initial site of bone tissue formation in a developing skeletal element. In long bones, the primary centre forms the diaphysis (shaft)...
- Scheuer-Black Framework
- The reference system for developmental skeletal age estimation published by Louise Scheuer and Sue Black in 'Developmental Juvenile Osteology' (Academic Press, 2000)....