Ch9 Joints

joint definition

where two bones (or cartilage) come together to form a sometimes movable structure

articulation

3 functional classifications of joints — movement

synarthrotic

amphiarthrotic

diarthrotic

3 structural classifications of joints — tissue

fibrous

cartilaginous

synovial

synarthrotic joint

immobile or nearly immobile

strong articulation

where are synarthrotic joints found

bones protecting internal organs

fibrous sutures of skull

cartilaginous manubriosternal joint

amphiarthrotic joint

limited mobility

amphiarthrotic joint: vertebral joints

include the fibrocartilage discs

minor movement between joints is allowed

amphiarthrotic joint: pubic symphysis

right and left coxal bones articulate via pad of fibrocartilage

diarthrotic joint

freely moveable joint

all synovial joints are included here

most are found in appendicular skeleton

3 subclassifications of diarthrotic joints

uniaxial

biaxial

multiaxial

diarthrosis: uniaxial joint (and example)

movement on a single plane

humerus and ulnar articulation only allows flexion/extension

diarthrosis: biaxial joint (and example)

movement in two planes

metocarpohalangeal (knuckle) joint allows flexion/extension, but also lateral/medial movement

diarthrosis: multiaxial joint (and example)

movement along three axes 

shoulder and hip joints allow anterior/posterior, medial/lateral, and rotation 

fibrous joints

bones articulate via fibrous connective tissue

subclassifications of fibrous joints

suture

syndesmosis

gomphosis

fibrous joints: suture

strong union between adjacent bones

typically classified as synarthrotic 

think skull 

fontanelle

connective tissue between skull plates in infants 

allows the skull to compress during birth

after birth they become sutures by ossification 

synostosis

fusion of two or more bones into one bone

fibrous joints: syndesmosis

parallel bones are united by fibrous connective tissue

syndesmosis: interosseous membrane (and examples)

narrow or wide gap between parallel bones spanned by connective tissue

radius and ulna — allows for rotation

tibia and fibula — locks talus between tibia and fibula

fibrous joints: gomphosis

fibrous joint that anchors the root of tooth to bony socket in maxilla or mandible 

called peg-and-socket joint

periodontal ligament

short bands of dense connective tissue fasten tooth within gomphosis joint

cartilaginous joint calssifications

synchondrosis

symphysis

cartilaginous joints: synchondrosis

bones joined by hyaline cartilage

permenant vs temporary synchondrosis example

sternocostal joint vs epiphyseal plate

epiphyseal plate

area of actively growing cartilage and bone during adolescence

fuses to a synestosis during adulthood

cartilaginous joints: symphysis

fibrocartilage joins bones

resistant to pulling and bending bc of collagen fibers

amphiarthrotic

examples of symphysis joints

intervertebral discs

pubic symphysis

manubriosternal joint

synovial joints

have a joint cavity 

articulating joints are not directly connected

synovial joints: articular capsule

fibrous structure attached to each bone outside of articulating surface

synovial joints: articular cartilage

thin layer of hyaline cartilage that covers articulating surface of each bone 

synovial joints: synovial membrane

lines inner surface of articular capsule and secretes synovial fluid for lubrication

ligament classifications

extrinsic ligament

intrinsic ligamen

intracapsular ligament

extrinsic ligament (and example)

located outside of joint capsule

ex. patellar ligament

intrinsic ligament

fused to or incorporated into wall of articular cappsule

intracapsular ligament

located inside articular capsule

tendon

dense connective tissue that attaches muscle to bone

articular discs // meniscus

may help join bones together

provides cushioning and shock absorption

bursa

thin connective tissue sac with lubricating fluid

located outside of synovial joint

where can you find bursas

where skin, ligaments, muscles, and/or tendons rub against each other

bursa classifications

subcutaneous bursa (patellar)

submuscular bursa (trochanteric)

subtendinous bursa (subacromial)

example of pivot joint

C1 and C2 with the dens

synovial joint: shoulder joint

ball and socket

tendons of several muscles blend with fibrous layer of joint capsule to form rotator cuff

synovial joint: elbow joint

two articulations

hinge between trochlea of humerus and trochlear notch of ulna

plane between capitulum of humerus and fovea of radius head

pivot joint of radial head on ulna

knee joint

largest and most complex synovial joint

condyles of femur and tibia

allows some rotation

hip joint

ball and socket joint

head of femur + acetabulum of hip bone

flexion vs extension

angle between two body parts is decreased vs increased

abduction vs adduction vs circumduction

movement away from midline vs toward midline vs combined

lateral vs medial rotation

synonymous with external vs internal rotation

supination vs pronation

palms up vs palms down

plantar flexion vs dorsiflexion

toes down vs toes up (ankle movement)

inversion vs eversion

sole of the foot toward the midline vs away from the midline

retraction vs protraction

posterior vs anterior movement

elevation vs depression

superior vs inferior movement

opposition

thumb and finger pads join