Joint

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For other uses, see Joint (disambiguation).

"Articulations" redirects here. For articulations in music, see Articulation (music).

A joint is the location at which two or more bones make contact.^[1] They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.^[2]

1 Classification
2 Arthritis
3 References
4 See also
5 External links

Classification

Depiction of an intervertebral disk, a cartilaginous joint.

Image:Illu synovial joint.jpg

Diagram of a synovial (diarthrosis) joint.

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 two 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

Structural classification names and divides joints according to how the bones are connected to each other.^[3] There are three structural classifications of joints:

fibrous joint - joined by fibrous connective tissue
cartilaginous joint - joined by cartilage
synovial joint - not directly joined

Functional classification

Joints can also be classified functionally, by the degree of mobility they allow:^[4]

synarthrosis - permits little or no mobility. Most synarthrosis joints are fibrous joints.
amphiarthrosis - permits slight mobility. Most amphiarthrosis joints are cartilaginous joints.

diarthrosis - permits a variety of movements. All diarthrosis joints are synovial joints, and the terms "diarthrosis" and "synovial joint" are considered equivalent by Terminologia Anatomica.^[5]

Biomechanical classification

Joints can also be classified based on their anatomy or on their biomechanical properties. According to the anatomic classification, joints are subdivided into simple and compound, depending on the number of bones involved, and into complex and combination joints:^[6]

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)

Anatomical

The joints may be classified anatomically into the following groups:

Arthritis

Main article: Arthritis

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.

References

^ eMedicine/Stedman Medical Dictionary Lookup!. Retrieved on 2008-01-29.
^ Ellis, Harold; Susan Standring; Gray, Henry David (2005). Gray's anatomy: the anatomical basis of clinical practice. St. Louis, Mo: Elsevier Churchill Livingstone, 38. ISBN 0-443-07168-3.
^ Module - Introduction to Joints. Retrieved on 2008-01-29.
^ Module - Introduction to Joints. Retrieved on 2008-01-29.
^ d_15/12293929 at Dorland's Medical Dictionary
^ Introductory Anatomy: Joints. Retrieved on 2008-01-29.

External links

v • d • e Joints
Types	fibrous: Gomphosis - Suture - Syndesmosis cartilaginous: Synchondrosis - Symphysis synovial: Plane joint - 1° (Hinge joint, Pivot joint) - 2° (Condyloid joint, Saddle joint) - 3° (Ball and socket joint) by range of motion: Synarthrosis - Amphiarthrosis - Diarthrosis
Terminology	Kinesiology - Anatomical terms of motion - Agonist/Antagonist
Motions	general: Flexion/Extension - Adduction/Abduction - Internal rotation/External rotation - Elevation/Depression specialized/upper limbs: Protraction/Retraction - Supination/Pronation specialized/lower limbs: Plantarflexion/Dorsiflexion - Eversion/Inversion
Components	Articular capsule (Synovial membrane, Fibrous membrane) - Synovial fluid - Bursa - Articular disk

v • d • e

Joints and ligaments of head and neck

Craniocervical

Atlanto-axial (lat + med)	capsule - atlantoaxial ligaments (anterior, posterior) - cruciform ligament of atlas (transverse ligament of the atlas)
Atlanto-occipital	capsule - membranes (anterior atlantoöccipital membrane - posterior atlantoöccipital membrane - tectorial membrane) alar ligament - ligament of apex dentis

Temporomandibular

capsule - articular disk
lateral (temporomandibular ligament) - medial (sphenomandibular ligament, stylomandibular ligament)

Other

Cricothyroid articulation - Cricoarytenoid articulation

v • d • e Joints and ligaments of upper limbs
Shoulder	sternoclavicular: anterior sternoclavicular - posterior sternoclavicular - interclavicular - costoclavicular acromioclavicular: acromioclavicular - coracoclavicular (trapezoid, conoid) - coracoacromial - superior transverse scapular - inferior transverse of scapula glenohumeral: coracohumeral - glenohumeral (superior, middle, and inferior) - transverse humeral - glenoid labrum
Elbow	humeroradial: radial collateral humeroulnar: ulnar collateral proximal radioulnar: annular - oblique cord
Forearm	distal radioulnar: volar radioulnar - dorsal radioulnar wrist/radiocarpal: palmar radiocarpal - dorsal radiocarpal - palmar ulnocarpal - ulnar collateral - radial collateral
Hand	intercarpal, midcarpal: pisohamate - scapholunate carpometacarpal: dorsal carpometacarpal - palmar carpometacarpal (pisometacarpal) intermetacarpal: deep transverse metacarpal - superficial transverse metacarpal metacarpophalangeal: palmar - collateral interphalangeal: palmar - collateral

v • d • e Joints and ligaments of torso
Vertebral column	articulations of vertebral bodies: anterior longitudinal ligament - posterior longitudinal ligament - intervertebral disc (annulus fibrosus, nucleus pulposus) articulations of vertebral arches : ligamenta flava - supraspinous ligament (nuchal ligament) - interspinal ligament - intertransverse ligament zygapophysial joint
Costovertebral	articulation of head of rib: radiate ligament - interarticular ligament costotransverse
Sternocostal	interarticular sternocostal ligament - radiate sternocostal ligaments - costoxiphoid ligaments interchondral, costochondral
Pelvis	articulation of the vertebral column with the pelvis: iliolumbar ligament sacroiliac: anterior sacroiliac ligament - posterior sacroiliac ligament - interosseous sacroiliac ligament ligaments connecting the sacrum and ischium: sacrotuberous ligament - sacrospinous ligament sacrococcygeal symphysis: anterior sacrococcygeal ligament - posterior sacrococcygeal ligament pubic symphysis: superior pubic ligament - inferior pubic ligament

v • d • e Joints and ligaments of lower limbs
Coxal/hip	femoral (iliofemoral, pubofemoral, ischiofemoral) - head of femur - transverse acetabular
Knee-joint	extracapsular: patellar - popliteal (oblique, arcuate) - collateral (medial/tibial, fibular/lateral) intracapsular: cruciate (anterior, posterior) - menisci (medial, lateral) - transverse
Tibiofibular	Superior tibiofibular: anterior of the head of the fibula - posterior of the head of the fibula Inferior tibiofibular: anterior of the lateral malleolus - posterior of the lateral malleolus
Talocrural/ankle	medial: medial of talocrural joint/deltoid (anterior tibiotalar, posterior tibiotalar, tibiocalcaneal, tibionavicular) lateral: lateral collateral of ankle joint (anterior talofibular, posterior talofibular, calcaneofibular)
Foot - subtalar/talocalcaneal	anterior/posterior - lateral/medial - interosseous
Foot - transverse tarsal	Talocalcaneonavicular: dorsal talonavicular - plantar calcaneonavicular/spring - bifurcated (calcaneonavicular) Calcaneocuboid: dorsal calcaneocuboid - long plantar - plantar calcaneocuboid - bifurcated (calcaneocuboid)
Foot - distal intertarsal	Cuneonavicular: plantar - dorsal Cuboideonavicular: plantar - dorsal Intercuneiform: plantar - dorsal - interosseous
Foot - other	Tarsometatarsal/Lisfranc: plantar - dorsal Intermetatarsal/metatarsal: plantar - dorsal - interosseous - superficial transverse - deep transverse Metatarsophalangeal: plantar - collateral Interphalangeal: plantar - collateral
Arches of the foot	Longitudinal - Transverse