Joints and Articulations

synarthroses

immovable joints

amphiarthroses

slightly movable joints

diarthroses

freely movable joints

Functional Classifications are:

synarthroses, amphiarthroses, diarthroses

fibrous joints

the bones are joined by fibrous tissues

Two major types of fibrous joints:

sutures and syndesmoses

Structural Classifications are:

Fibrous, cartilaginous, and synovial

cartilaginous joints

the articulating bone ends are connected by a plate or pad of cartilage

Synovial

are those in which the articulating bone ends are separated by a joint cavity containing synovial fluid.

Six major types of synovial joints

Plane, hinge, pivot, ball and socket, condyloid, saddle

plane (gliding)

articulating surface are flat or slightly curved, allowing sliding movements in one or two planes. ex: intercarpal and intertarsal joints

hinge

the rounded process of one bone fits into the concave surface of another to allow movement in one plane(uniaxial), usually flexion and extension. ex: elbow and interphalangeal joints

ball-and-socket

the ball shaped head of one bone fits into a cuplike depression of another (multiaxial) allowing movement in all directions and pivotal rotations. ex: shoulder and hip joints

Movements of synovial joints are: (12)

flexion, extension, adduction, abduction, circumduction, rotation, supination, pronation, inversion, eversion, dorsiflexion, plantar flexion

extension

a movement that increases the angle of the joint and the distance between the 2 bones or parts of the body.

adduction

movement of a limb toward the midline of the body ex: brining fingers and toes back to midline

circumduction

a combination of flexion, extension, abduction, and adduction commonly observed in ball-and-socket joints like the shoulder distal end moves in a circle while proximal end is stationary

eversion

a movement that results in the lateral turning of the sole of the foot

dorsiflexion

a movement of the ankle joint in a dorsal direction Ex: standing on one heel

plantar flexion

a movement of the ankle joint in which the foot is flexed downward. Ex: standing on one's toes or pointing the toes

sutures

irregular edges of the bone interlock and are united by very short connective tissue fibers. ex: skull

syndemoses

the articulating bones are connected by short ligaments of dense fibrous tissue; the bones do not interlock.

two major types of cartilaginous joints

symphyses and synchondroses

symphyses

the bones are connected by a broad, flat disc of fibrocartilage. ex: interveterbral joints and pubic symphasis of the pelvis

synchondroses

the bony portions are united by hyaline cartilage. ex: epiphyseal plates seen in the long bones of growing children.

pivot

the rounded or conical surface of one bone articulates with a shallow depression or foramen in another bone. Pivot joints allow uniaxial rotation. ex: in the proximal radioulnar joint and the joint between the atlas and axis.

condyloid (ellipsoidal)

the oval condyle of one bone fits into an ellipsoidal depression in another bone, allowing biaxial (two-way) movement. ex: radiocarpal (wrist) joint and the metacarpophalangeal joints

saddle

articulating surface are saddle- shaped; the articulating surface of one bone is convex and the reciprocal surface is concave (biaxial). ex: joint between the thumb metacarpal and the trapezium of the wrist.

flexion

a movement that decreases the angle of the joint and reduces the distance between the 2 bones. ex; bending the knees or elbows

abduction

movement of a limb away from the midline or median plane of the body, generally on the frontal plane. ex: fanning movement of the fingers or toes

rotation

movement of a bone around its longitudinal axis without lateral or medial displacement. ex: turning your head to represent no

pronation

movement of the palm of the head from an anterior or upward-facing position to a posterior or downward facing position. ex: the distal end of the radius moves across the ulna

supination

movement of the palm from a posterior position to an anterior position(anatomical position). ex: the radius and ulna are in parallel position

inversion

a movement that results in the medial turning of the sole of the foot