Joints (Articulations)

A joint, or an articulation, is a place where two bones come together. A joint is usually considered movable, but that is not always the case. Many joints exhibit limited movement, and others are completely, or almost completely, immovable

• Weakest parts of the skeleton
• Articulation – site where two or more bones meet

1.1 Functions

• • Give the skeleton mobility
  • Hold the skeleton together

1.2 Structural and Functional Classification

1. By function – degree of movement
2. By structure – presence of cavity
3. 1.2.1 Classification of Joints: Structural
4. •      Structural classification focuses on the material binding bones together and whether or not a joint cavity is present.
5. •      The three structural classifications are:
6. Fibrous
7. Cartilaginous
8. Synovial
9. 1.2.2 Classification of Joints: Functional
10. •      Functional classification is based on the amount of movement allowed by the joint.
11. •      The three functional class of joints are:
12. Synarthroses – immovable
13. Amphiarthroses – slightly movable
14. Diarthroses – freely movable

1.2.1.1 Fibrous Joints or Fixed Joints

• The bones are jointed by fibrous tissues

Eg. joint are the sutures of the skull.

• There is no joint cavity.
• Most are immovable.
• There are three  types –

1. Sutures
2. Syndesmoses
3. Gomphoses

Figure 1- Fibrous Joint

Table 1- Types of Fibrous Joints

Figure 2- (a) Sutures (b) Syndesmoses (c) Gomphoses