Anatomy of Joints: Types, Movements, and Structural Classifications

Synarthrosis

A functional classification of articulations in which the joint allows no motion between the bones.

Amphiarthrosis

A functional classification of articulations in which the joint allows for only a small amount of motion between articulating bones.

Diarthrosis

A functional classification of articulations in which the joint allows for a wide range of motion between articulating bones.

Fibrous joint

A structural classification of articulations in which the joints are held together by dense regular collagenous connective tissue and have neither a synovial cavity nor an articular capsule.

Cartilaginous joint

A structural classification of articulations in which joints are held together by cartilage and have neither a synovial cavity nor an articular capsule.

Synovial joint

A structural classification of articulations in which the joints have a fluid-filled synovial cavity between articulating bones that are enclosed within an articular capsule.

Suture

A fibrous joint structurally and a synarthrosis functionally that is found between the bones of the skull.

Gomphosis

A fibrous joint structurally and a synarthrosis functionally that is found between each tooth and the bony socket in either the mandible or the maxilla.

Syndesmosis

A fibrous joint structurally and an amphiarthrosis functionally in which the articulating bones are joined by an interosseous membrane or ligament.

Synchondrosis

A cartilaginous joint structurally and a synarthrosis functionally in which the articulating bones are held together by hyaline cartilage.

symphysis

a cartilaginous joint structurally and an amphiarthrosis

functionally in which the articulating bones are connected by a

fibrocartilaginous pad.

Epiphyseal plate

A structure composed of hyaline cartilage from which long bones grow in length. An example of a synchondrosis joint.

joint

the location where two or more bones come together; also known

as an articulation

synovia Joint

a structural classification of articulation in which the joints

have a fluid-filled space between the articulating bones of a synovial

joint.

Synovial fluid

The fluid secreted by the synovial membrane to provide lubrication, shock absorption, and nutrients to the articulating bones and articular cartilage as well as providing a medium in which metabolic functions can occur.

Articular capsule

A double layered structure surrounding synovial joints that holds the articulating bones together.

Ligament

A strand of dense regular collagenous connective tissue that connects one bone to another to strengthen and reinforce the articulation.

Tendon

Structural component of skeletal muscle, composed of dense regular collagenous connective tissue which connects muscle to bone.

Bursa

A synovial fluid-filled structure located between bones, tendons, and muscles of certain synovial joints; minimizes friction between moving parts.

Bursitis

Inflammation of a bursa.

Arthritis

Inflammation of one or more joints that results in pain and limitation of joint movement.

Osteoarthritis

Most common form of arthritis and is associated with advanced age and wear and tear on the joints.

Rheumatoid arthritis

Arthritis that is auto-immune.

Gouty arthritis

Inflammation (usually of the great toe) due to uric acid crystal deposits.

Flexion

Decreases the angle between articulating bones by bringing the bones closer together.

Extension

Increases the angle between articulating bones.

Hyperextension

Extension beyond the anatomical position of the joint.

Abduction

An angular movement whereby the body part moves away from the midline of the body or another reference point.

Adduction

An angular movement whereby the body part moves toward the midline of the body or another reference point.

Circumduction

An angular movement that is the sum total of flexion-extension and abduction-adduction; results in a cone-like motion best seen in the hip and shoulder joints.

Rotation

A nonangular motion in which one bone rotates or twists on an imaginary line running down its middle or longitudinal axis.

Opposition

The special movement that occurs only at the first carpometacarpal joint, in which the thumb travels across the palmar surface of the hand.

Reposition

The movement of the first carpometacarpal joint back to anatomical position from an opposed position.

Depression

The movement of a joint in which the corresponding body part moves in an inferior direction.

Elevation

The movement of a joint in which the corresponding body part moves in a superior direction.

Protraction

The movement of a joint in which the corresponding body part moves in an anterior direction.

Retraction

The movement of a joint in which the corresponding body part moves in a posterior direction.

Inversion

A rotational movement of the foot in which the plantar surface rotates medially toward the midline of the body.

Eversion

A rotational movement of the foot in which the plantar surface rotates laterally away from the midline of the body.

Dorsiflexion

An angular movement of the foot at the ankle in which the angle between the foot and the leg decreases.

Plantarflexion

An angular movement of the foot at the ankle in which the angle between the foot and the leg increases.

Supination

Rotational movement (ex: arm is supinated when palm faces forward as in anatomical position).

Pronation

Rotational movement of the wrist and ankle (pronation turns palms inferiorly or posteriorly and radius crosses over ulna).

Hinge joint

A uniaxial joint in which the convex articular surface of one bone fits into the concave depression of the other bone, creating a hinge that allows for motion around one axis. Example: elbow and knee joints.

Pivot joint

A uniaxial joint in which the rounded surface of one bone fits into the groove on the surface of another bone allowing for rotational movement around one axis.

Ball and socket joint

A multiaxial joint in which the articulating surface of one bone is ball shaped and fits into a cup shaped socket in the other bone, allowing for movement around three axes.