Structures and types of joints

Synarthrosis

immovable joint, uninterrupted

connected by CNT: syndesmosis, suture, gomphosis

connected by cartilage and bone tissue: synchondrosis, symphysis, synostosis

Syndesmosis

bones connected by ligaments

Ex: interosseous membrane of forearm and leg

suture

dense CNT; between bones of calvaria and skull

Gomphosis

attachment of a tooth to its socket; periodontal ligament

Synchondrosis

bones are bound by hyaline cartilage

Ex. rib attachment to sternum by costal cartilage

symphysis

two bones joined by fibrocartilage; pubis symphysis, vertebrae

Synostosis

fusion of bones; sacrum, hip bone

Diarthrosis (synovial joint)

freely movable joint, interrupted

main components of synovial joints

articular surfaces

articular cartilage

joint capsule

synovial fluid

articular ligament

articular cartilage

hyaline or fibrocartilage (less common); covers the ends of bones; easy movements

joint capsule

dense fibrous CNT; seals joint cavity

fibrous capsule (stratum fibrosum): external

synovial membrane (stratum synoviale): internal

synovial fluid

lubricant

articular ligaments

fibrous CNT; reinforce joint capsule

accessory components of synovial joint

fibrocartilaginous articular lips, meniscus, discus, articular bursa, articular sheath, articular muscles

Meniscus

fibrocartilage; compensate for misalignment (knee joint)

discus

fibrocartilage; divide joint cavity into 2 parts (sternoclavicular joint)

plane joint (amphiarthrosis)

permit gliding of structures

Ex: intercarpal joints, intertarsal joints

pivot joint

uniaxial; rotations

Ex: atlantoaxial joint, inferior and superior radioulnar joint

hinge joint

uniaxial; motion in one axis (flexion and extension)

Ex: interphalangeal joint

trochoginglymus joint

combination of pivot and hinge joints

Ex: knee joint, elbow joint

Condylar (ellipsoid) joints

biaxial; movements if 2 planes (flexion/extension, abduction/adduction)

Ex: metacarpophalangeal joint, wrist joint

saddle (sellar) joint

biaxial; movements in 2 planes

interlocking saddle-shaped articular surface

Ex: 1st carpometacarpal joint (opposition/reposition)

ball and socket joint

multiaxial; movements in 3 planes

Ex: hip joint, shoulder joint

compound joint

A joint in which three or more bones articulate

Ex: knee joint, elbow joint