Highlighted in blue are the cement lines which mark the boundaries of present and former osteons.
Each osteon consists of parallel, concentric lamellae surrounding a Haversian canal.
These lines indicate the shape of the surface upon which osteoblasts began laying down fresh lamellae after osteoclasts had excavated a channel throught the bone.
The patterns of lamellae reflect the history of bone remodelling. Osteons with complete concentric lamellae are the most recently formed. Other lamellae, which terminate abruptly against a cement line, are the fragmentary remains of former osteons that have been partially removed and replaced during remodelling.
- Number 1 indicates a recently formed osteon.
- Number 2 indicates a somewhat older osteon, as demonstrated by the encroachment of osteon 1.
- Number 3 indicates interstitial lamellae, representing the remnants of still older osteons.
Click on a thumbnail below for additional information.
Comments and questions: dgking@siu.edu
SIUC / School
of Medicine / Anatomy / David
King
http://www.siumed.edu/~dking2/ssb/NM035b1.htm
Last updated: 12 December 2003 / dgk
