Enthesis
Overview
Enthesis (plural: entheses) is the point at which a tendon inserts into bone, where the collagen fibers are mineralized and integrated into bone tissue. These insertion points are commonly called Sharpey’s fibers.
Classification
There are two types:
- Fibrous entheses
- Fibrocartilaginous entheses
In a fibrous enthesis, the collagenous tendon or ligament directly attaches to the bone, whilst the fibrocartilaginous enthesis displays 4 zones during the transition from tendon/ligament to bone:
- i) tendinous area displaying longitudinally oriented fibroblasts and a parallel arrangement of collagen fibres
- ii) a fibrocartilaginous region of variable thickness where the structure of the cells changes to chondrocytes
- iii) an abrupt transition from cartilaginous to calcified fibrocartilage – the so-called ‘tidemark’ or ‘blue line’
- iv) bone
Pathology
A disease of the entheses is known as an “enthesopathy” or “enthesitis” and is characteristic of spondyloarthropathy but present in other pathology as well.
External links
- Image of enthesis at Medscape
- Enthesopathy and Soft Tissue Shadows at chiroweb.com
- Resnick D, Niwayama G (1983). “Entheses and enthesopathy. Anatomical, pathological, and radiological correlation”. Radiology. 146 (1): 1–9. PMID 6849029.
- Template:Medcyclopaedia
- Origin of phrase at rheuma21st.com at rheuma21st.com
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