Human Anatomy - Joints

acetabul

vinegar cup

anul

ring

arth

joint

burs

bag

condyl

knob

fov

pit

glen

joint socket

labr

lip

ov

egglike

sutur

sewing

syndesm

binding together

Fibrous joints

• dense connective tissue that holds them together has many collagenous fibers

• between bones that are in close contact

types of fibrous joints

• syndesmosis

• suture

• gomphosis

syndesmosis joint

• bones bound by sheet of dense connective tissue or bundle of dense connective tissue

• slight movement (amphiarthrotic)

example of syndesmosis joint

between tibia and fibula

suture

• only between flat bones of skull

• margins of adjacent bones grow together and unite by thin layer of dense connective tissue aka sutural ligament

• immovable (synarthrotic)

example of suture

coronal suture

gomphosis joint

• joint formed by union of a cone-shaped bony process in a bony socket

• synarthrotic (don’t move)

gomphosis joint example

tooth root to jaw

Cartilaginous joints

• joints connected by hyaline cartilage or fibrocartilage

types of cartilaginous joints

• synchondrosis

• symphysis

synchondrosis

• bands of hyaline cartilage unite bones

• many temporary

  • disappear during growth

• synarthrotic

synchondrosis example

• between the manubrium and the first rib

symphysis

• articular surfaces of bones covered by thin layer of hyaline cartilage

• cartilage is attached to pad of springy fibrocartilage

• limited movement

symphysis example

pubic symphysis

Synovial joints

• allow free movement (diarthrotic)

• articular cartilage

• a joint capsule

• synovial membrane that secretes synovial fluid

synovial joint structure

• articular ends of bones covered in hyaline cartilage

• tubular joint capsule with 2 layers holds together bones

• ligaments reinforce joint capsule and help bind the articular ends of bones

• synovial membrane covers all surfaces within joint capsule except those covered by articular cartilage

• synovial fluid

  • secreted by synovial membrane

  • lubricant

• menisci - fibrocartilage discs

  • divide joint in 2

• bursae

  • fluid filled sacs

  • cushion

types of synovial joints

• ball and socket joint

• condyloid joint

• gliding joint

• hinge joint

• pivot joint

• saddle joint

ball and socket joint

• bone with globular/slightly egg shaped head

• articulates with cup-shaped cavity of another bone

• wide range of motion

  • yes rotational movement

• examples

  • hip and shoulder

condyloid joint

• ovoid condyle of one bone fits into elliptical cavity of another bone

• variety of movement

  • no rotational movement

• example

  • joints btwn metacarpals and phalanges

gliding joints

• articulating surfaces nearly flat or slightly curved

• allow sliding back & forth motion & twisting movements

• examples

  • joints in wrist and ankle

hinge joint

• convex of one bone fits in concave surface of another

• movement in one plane only

• example

  • elbow

pivot joint

• cylindrical surface of one bone rotates withing ring made of bone and a ligament

• rotation around central axis only

• example

  • joint between proximal ends of the radius and ulna

saddle joint

• between bones whose articulating surfaces have both concave and convex regions

• surface of one bone fits surface of the other

• variety of movement

  • mostly in 2 planes

• example

  • joint between trapezium and metacarpal of thumb

flexion

bending parts at a joint so the angle of between them decreases and the parts come closer together (bending knee)

extension

straightening parts at a joint so that the angle between them increases and the parts move farther apart (straightening knee)

hyperextension

excess extension of the parts at a joint beyond the anatomical position (bending head back beyond anatomical position)

dorsiflexion

movement at the ankle that brings the foot closer to the shin (walking on heels)

plantar flexion

movement at the ankle that brings the foot farther from the shin (walking or standing on toes)

abduction

moving a part away from the midline (lifting upper limb horizontally to form right angle with body)

adduction

moving a part toward the midline (returning the upper limb from the horizontal position to the side of the body)

rotation

moving a part around an axis (head side to side)

• medial rotation is movement toward midline

• lateral rotation is movement toward outside

circumduction

moving a part so that its end follows a circular path (moving finger in circle w/out moving hand)

supination

turning the hand so the palm is upward or facing anteriorly

pronation

turning the hand so the palm is downward or facing posteriorly

eversion

turning the foot so the plantar surface faces laterally

inversion

turning the foot so the plantar surface faces medially

protraction

moving a part forward (thrusting chin)

retraction

moving a part backward (pulling chin backward)

elevation

raising a part (shrugging shoulders)

depression

lowering a part (drooping the shoulders)

shoulder

• bones

  • humerus

  • scapula

• ligaments

  • coracohumeral

  • glenohumeral

  • transverse humeral

elbow

• bones

  • humerus

  • radius

  • ulna

• ligaments

  • ulnar collateral

  • radial collateral

hip

• bones

  • acetabulum of coxa

  • femur

• ligaments

  • iliofemoral

  • pubofemoral

  • Ischiofemoral

  • ligamentum capitis

knee

• bones

  • femur

  • patella

  • tibia

  • fibula

• ligaments

  • oblique popliteal

  • acuate popliteal

  • tibial collateral

  • patellar

  • fibular collateral

  • cruciate

how are joints classified

by the type of tissue that binds the bones at each junction

meniscus definition

a fibrocartilage disc that divides a synovial joint into two compartments

bursa definition

a fluid filled sac in a synovial joint

why does the shoulder joint have a wide range of movement

because of the looseness of its attachments and the relatively large articular surface of the humerus compared to the shallow depth of the glenoid cavity

what is the function of the menisci of the knee

they separate the articulating surfaces of the femur and tibia and help to align them

location of the bursae of the knee joint

• between the anterior surface of the distal end of the femur and the muscle group above it

• between the patella and the skin

• between the proximal end of the tibia and the patellar ligament

fibrous joints aging

• fontanels of skull close

• joints accumulate bone matrix over time

• strengthen with time

synovial joints aging

• begins in 30s

• circulation of synovial fluids slows

• synovial membrane becomes infiltrated with fibrous material

• causes joint to stiffen

• collagen cross-links stiffen and shorten

• affect range of motion & balance

cartilaginous joints aging

• less water in intervertebral discs

• less flexibility in vertebral column

• restricts person’s range of motion over time

• dics can slightly collapse on themselves → height loss