Related Experiment Video
Updated: Jul 3, 2026

Culture of Murine Embryonic Metatarsals: A Physiological Model of Endochondral Ossification
Published on: December 3, 2016
Evidence for a distinctive pattern of bone formation in enthesophytes
M Benjamin1, H Toumi, D Suzuki
1Cardiff University, UK. Benjamin@cardiff.ac.uk
Objectives:
The mechanism of new bone formation at entheses in spondyloarthritis (SpA) is poorly understood, but it is a key factor contributing to disability in disease. As bony spur development is also an age-related phenomenon, spurs in elderly dissecting room cadavers were studied in order to establish general principles relating to their development.
Methods:
Spurs of different sizes were studied by routine histology at 26 different entheses (a total of 76 specimens) from the upper limb, lower limb and spine. The percentage of bone:marrow was compared in the posterior part of the calcaneus in cadavers with and without Achilles spurs to ascertain the relationship between spurs and immediately adjacent trabecular bone.
Results:
Bony spur formation was a common age related phenomena and typically occurred in the most fibrous part of an enthesis. Paradoxically, it was often heralded by the initial appearance of a thick zone of calcified fibrocartilage that subsequently developed bony nodules within it. Uncalcified fibrocartilage was more prominent around large spurs. Endochondral, intramembranous and chondroidal ossification all contributed to spur formation and growth, but cell hypertrophy and florid vascular invasion of a cellular calcified cartilage, typical of endochondral ossification, were not conspicuous features.
Conclusion:
Entheseal new bone formation occurs by a combination of three methods of ossification. However, endochondral ossification was atypical and differed from that seen in the normal development of cartilage bones or during fracture healing. How the inflammatory process modulates these processes could lead to a better understanding of entheseal new bone formation in SpA.
Related Concept Videos
The Evidence for Evolution
Bone Formation by Endochondral Ossification
Bone Markings
Articulating Projections
Articulating projections are found where two bones meet to form a joint. These structures are usually found at the ends of bones. The largest articulation is a rounded projection called the head, supported by a narrow neck at the ends of...
Bone Formation by Intramembranous Ossification
The process begins when mesenchymal cells in the embryonic skeleton gather together and differentiate into osteogenic cells, which then develop into...
Development of the Limb Synovial Joints
The mesenchymal stem cells differentiate into chondrocytes that form the hyaline cartilage, and later the cartilaginous model of the bone. This model further transforms into a bone. This process is known as endochondral ossification.
During development, the limbs...
Growth of Cartilage and Bone Tissue
