is the location at which two or more bones
make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.
Joints are mainly classified structurally and functionally. Structural classification is determined by how the bones connect to each other, while functional classification is determined by the degree of movement between the articulating bones. In practice, there is significant overlap between the seven types of classifications.
Terms ending in the suffix -sis are singular and refer to just one joint, while -ses is the suffix for pluralization.
Structural classification names and divides joints according to how the bones are connected to each other. There are three structural classifications of joints:
Joints can also be classified functionally, by the degree of mobility they allow:
Joints can also be classified based on their anatomy or on their biomechanical properties. According to the anatomic classification, joints are subdivided into simple
, depending on the number of bones involved, and into complex
- Simple Joint: 2 articulation surfaces (eg. shoulder joint, hip joint)
- Compound Joint: 3 or more articulation surfaces (eg. radiocarpal joint)
- Complex Joint: 2 or more articulation surfaces and an articular disc or meniscus (eg. knee joint)
The joints may be classified anatomically into the following groups:
- Articulations of hand
- Elbow joints
- Wrist joints
- Axillary articulations
- Sternoclavicular joints
- Vertebral articulations
- Temporomandibular joints
- Sacroiliac joints
- Hip joints
- Knee joints
- Articulations of foot
Arthritis and direct physical trauma
to a joint are the causes of joint damage. Arthritis is a group of conditions where there is damage caused to the joints
of the body. Arthritis is the leading cause of disability in people over the age of 55.
There are many different forms of arthritis, each of which has a different cause. The most common form of arthritis, osteoarthritis (also known as degenerative joint disease) occurs following trauma to the joint, following an infection of the joint or simply as a result of aging. Furthermore, there is emerging evidence that abnormal anatomy may contribute to early development of osteoarthritis. Other forms of arthritis are rheumatoid arthritis and psoriatic arthritis, which are autoimmune diseases in which the body is attacking itself. Septic arthritis is caused by joint infection. Gouty arthritis is caused by deposition of uric acid crystals in the joint that results in subsequent inflammation. Additionally, there is a less common form of gout that is caused by the formation of rhomboidal shaped crystals of calcium pyrophosphate. This form of gout is known as pseudogout.