Joints and movements

skeletal framework of the body

Joint

An area where 2 or more bones meet

Join other name

articulation

functions of joints

hold bones together, allow for mobility, classified according to structure

Classification of joints

fibrous/fixed, cartilaginous, synovial

fibrous joints

immovable, held together by connective tissue, strong

cartilaginous joints

slightly moveable, held in place by cartilage, stronger than synovial

cartilaginous examples

pubic, symphysis, intervertebral discs

fibrous examples

sutures of skull, teeth and jaw

synovial

freely movable, ligaments, muscles and tendons control movement, more easily damaged

synovial examples

shoulder and knee joint

structure of synovial joints

articular capsule made of fibrous capsule, synovial membrane, articular cartilage, articular discs, bursae, ligaments

articular capsule

surrounds entire joint and made of fibrous capsule and synovial membrane

fibrous capsule

outer layer, dense connective tissue attached to bones. flexible enough, allowing movement but strong enough for no dislocation

synovial membrane

inner layer or capsule, loose connective tissue. Lines the entire cavity, well supplied with blood vessels

articular capsule

covers surfaces of bones to reduce friction on surfaces

articular discs (meniscus in knee)

direct synovial fluid into areas of greates need, like articulating surfaces

bursae

sacs of synovial fluid preventing friction between features like tendons/joints/skin and bones

ligaments

join bone to bone, adds strength to joints

structure and function of synovial fluid

synovial fluid, functions: lubricates, provides nourishment, contains phagocytes

synovial fluid

secreted by synovial membrane and fills synovial cavity

function of synovial fluidm (lubricates, nourishment, phagocytes)

lubricates joints and keeps two surfaces of bones from rubbing eachother, provides nourishment for cartilage cells, contains phagocytes to destroy any pathogens/debris from wear nd tear

function of synovial fluid

lubricates, nourishment, phagocytes

injury to a synovial joint

increase the synovial fluid leading to inflammation

structure of synovial joint

types of synovial joints 6

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

ball and socket joint

spherical head of a bone fits into a cup-like depression of anotherbone, allows for a very large range of motion

examples of ball and socket joint

shoulder and hip joint

hinge joint

convex surface of one bone fits into concave of another, allows movement on a plane back and forth/flexion and extension

EXAMPLES OF HINGE JOINT

elbow and knee joint

pivot joint

poiinted end of a bone articulates with a ring of bone/ligament, allows for rotation

examples of a pivot joint

first and second, vertebrae (head rotation, radius and ulna

gliding joint

two bones that move alongside one another, allows for limited movement in either side-to-side or back-and-forth

examples of gliding joint

between carpal bones, sternum and clavicle

saddle joint

concave and convex bones fit together like a saddle

examples of a saddle joint

thumb joining to hand, metacarpal to carpal

condyloid joint

slightly convex bone fits into slightly concave bone, allows for limited range of motion both side to side and back and forth

examples of a condyloid joint

between phalanges and metacarpals, radius and carpals

keeping joints together, factors that keep the articular surfaces of synovial joints together

the fit of the articulating bones, the strength of joint ligaments, the tension provided by the muscles around the joint

the fit of articulating bones example

the way the head of the humerus fits into the socket of the scapula to form the shoulder joint

the strength of the joint ligaments holding the bones together example

hip joint

the tension provided by the muscles around the joint example

in the knee joint, the fibrous capsule is formed principally from tendons attached to the muscles acting on the joint

movement at joints

flexion and extension, abduction and adduction, rotation

flexion

decreases angle between articulating bones, e.g when the elbow is flexed, the lower arm with raidus and ulna moves closer to the upper arm with the humerus

extension

increases angle between articulating bones e.g when the knee is extended, the lower leg with tibia and fibula moves away further away from the upper leg with the fermur

abduction

movement away from midline of the body like lifting arms away from body

adduction

movement towards midline of the body like bringing arms inwards towards the body

rotation

movement along the long axis of a bone, like moving head left to right