Arthrology (ARTHROLOGIA) - the science of bones connection
- Category: Musculoskeletal system
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The connections of the bones - articulatio.
Development of the bones connections.
On 6-7 th week between the cartilage bones models occurs the concentration of mesenchyme. Then development of the bones connections goes by two ways:
1) from the mesenchyme forms fibrous or cartilaginous tissue (development of the uninterrupted bones connection);
2) liquefaction of the mesenchyme (development of the interruptions bones connection).
Classification of the bones connections:
I. Uninterrupted connection - synarthrosis:
1.1. Fibrous connection:
1.1.1. Syndesmosis - connection of the bones by ligaments and membranes.
1.1.2. Connection of the bones skull.
1.1.3. Herniation –zubo alveolar connection.
1.2. Cartilage connection - synchondrosis;
1.3. Bone connection - synostosis
II. Discontinuous connection - diarthrosis;
Discontinuous connection is the joint.
The joint is the body which has main and auxiliary elements.
Main elements (always present in every joint) of the joint:
- Joint surfaces
- Articular cartilage
- Joint capsule. The capsule has two layers: the outer - fibrous membrane, and inner - synovial membrane. Synovial membrane can form the folds and the bags.
- Articular cavity
- Synovial fluid.
Auxiliary elements (can not be part of the joint) of the joint:
- Articular disc
- Articular meniscus
- Articular lip
Joints are divided (classified) into 4 types:
I. Simple joint - one pair of articular surfaces.
II. Complex joint - two or more pairs of articular surfaces.
III. Comprehensive joint - articular cavity divided by disc or meniscus into parts (storeys, departments).
IV. The combined joint - separate joints together perform the movement.
Depending on the shape of the articular surfaces, are distinguished the following forms (species) of the joints:
1. Block shaped joint
2. Spiral joint
3. Cylindrical joint
4. Ellipse joint
5. Outgrowth joint
6. Saddle joint
7. Spherical joint
8. Cup-shaped joint
9. Flat joint.
By function joints are divided into:
- Uniaxial joint - movements occur around one axis (forms 1-3);
- Two-axial joint - movements occur around two axes (forms 4-6);
- Three-axial joint - movements occur around three axes (forms 7-9).