CHAPTER 9 joints

articulations

place where a bone meets another…

• bone, cartilage, or teeth

• vary in stability and mobility

• more mobility = less stability

classification by structures

• fibrous

• cartilaginous

• synovial

classification by function

• synarthrosis

• amphiarthrosis

• diarthrosis

synarthrosis

immobile joint

amphiarthrosis

slightly mobile joint

diarthrosis

freely moveable joint

fibrous joint

bones held together by dense regular CT

3 types:

1. gomphosis

2. sutures

3. syndesmoses

gomphoses

joints between teeth

• synarthroses

sutures

joints between skull bones

• synarthroses

syndesmoses

joints between parallel bones

• in the forearm (radius, ulna)

• in the leg (tibia, fibula)

• amphiarthroses

cartilaginous joints

bones joined by cartilage

2 types:

1. synchondroses

2. symphyses

synchondroses

bones joined by hyaline cartilage

• synarthroses

example:

• costal cartilage

symphyses

bones joined by fibrocartilage

• amphiarthroses

examples:

• pubic symphysis

• intervertebral disc

synovial joints

bones separated by fluid-filled joint cavity

• freely mobile diarthroses

general anatomy of synovial joints

• articular capsule

• articular cartilage

• joint cavity

• ligaments

• sensory nerves

• blood vessels

• accessory structures

articular capsule

2 layers

1. outer fibrous layer

   • made of dense regular CT

   • strengthens joint

2. inner synovial membrane

   • secretes synovial fluid

articular cartilage

articular surfaces in synovial joints covered by hyaline cartilage

• reduces friction and acts as shock absorber

joint cavity

spaces between articulating bones

• contains small amount of synovial fluid

synovial fluid

• lubricates and nourishes articular cartilages

• nourishes chondrocytes of articular cartilage

• absorbs shock during compression of joint

ligaments

connect bone to bone

• dense regular CT

• strengthen and reinforce capsule

sensory nerves

detect pain and amount of stretch in a joint

blood vessels

nourishes tissues in the joint

accessory structures surrounding synovial joint

• bursae

• tendon sheath

• fat pads

bursae

fluid filled sac where ligaments, muscles, tendons, and/or bones rub

• contain synovial fluid

tendon sheath

elongated bursae around tendons where tendon rub each other

fat pads

packing material

• also provide some protection

first class lever

has fulcrum in the middle: RFE

example:

• seesaw

• atlanto-occipital joint

second class lever

has resistance in the middle: ERF

example:

• lifting handle of wheelbarrow

• bouncing knee, hip joint is fulcrum

third class lever

has effort in the middle: REF

example:

• paddling canoe

• forearm when flexing elbow

uniaxial

joint moves in 1 plane or axis

biaxial

joint moves in 2 plane or axis

multiaxial

joint moves in 3 plane or axis

movements of synovial joints

4 types of motion

1. gliding motion

2. angular motion

3. rotational motion

4. special movement

gliding motion

articular surfaces sliding

• back and forth

• side to side

occurs mainly in plane joints

example:

• between carpals

angular motion

increases or decreases the angle between bones

• flexion vs extension

• abduction vs adduction

• hyperextension

• lateral flexion

• circumduction

rotational motion

a bone turning on its longitudinal axis

• lateral rotation vs medial rotation

• pronation vs supination

examples:

• atlantoaxial joint turning back and forth in the “no” gesture

• limbs turning to and from median plan

special movements

occur only at specific joints

• depression vs elevation

• dorsiflexion vs plantar flexion

• inversion vs eversion

• protraction vs retraction

• opposition

temporomandibular joint

between mandibular condyle and temporal bone

• hinge joint

• articular disc

• ligaments

  • sphenomandibular ligament

  • stylomandibular ligament

  • temporomandibular (lateral) ligament

intervertebral articulations

amphiarthroses between vertebral bodies

diarthroses between articular processes

vertebral bodies separated by intervertebral disc

ligaments:

• anterior longitudinal ligament

• posterior longitudinal ligament

joints of pectoral girdle and upper limbs

selected joints include:

1. sternoclavicular joint

2. acromioclavicular joint

3. glenohumeral (shoulder) joint

4. elbow joint

5. radiocarpal (wrist) joint

sternoclavicular joint

between manubrium of sternum and sternal end of clavicle

• saddle joint

• ligaments

  • anterior and posterior sternoclavicular ligament

  • costoclavicular ligament

  • interclavicular ligament

acromioclavicular joint

between acromial end of clavicle and acromion of scapula

• ligaments

  • acromioclavicular joint

  • coracoclavicular joint

glenohumeral joint

between head of humerus and glenoid cavity of scapula

• ball and socket joint

features

• fibrocartilaginous glenoid labrum

• ligament

  • coracoacromial ligament

  • corahumeral ligament

  • glenohumeral ligament

  • transverse humeral ligament

• rotator cuff muscles

• bursae

  • subacromial bursae

  • subcoracoid bursae

  • subdeltoid bursae

  • subscapular bursae

elbow joint

composed of humeroulnar and humeroradial joints

• hinge joint and pivot joint

• ligaments

  • radial (lateral) collateral ligament

  • ulnar (medial) collateral ligament

  • annular ligament

radiocarpal joint

between…

distal articular surface of radius

and three proximal carpal bones (scaphoid, lunate, triquetrum)

• condylar joint

• diarthrotic

joints of the pelvic girdle and lower limbs

selected joint include

• hip (coxal) joint

• knee joint

• talocrural (ankle) joint

• joints of the foot

coxal joint

between head of femur and acetabulum of os coxae

• ball and socket joint

• articular capsule with retinacular fibers

• ligaments:

  • iliofemoral ligament

  • ishiofemoral ligament

  • pubofemoral ligament

  • ligaments of head and femur

knee joint

between femur, tibia, and patella

• hinge joint

largest and most complex joint in body with

• medial and lateral menisci

• ligaments

  • patellar ligament

  • fibular (lateral) collateral ligament

  • tibial (medial) collateral ligament

  • anterior and posterior crucial ligaments (ACL and PCL)

talocrural joint

composed of two articulations

1. between distal end of tibia and talus

2. between distal end of fibula and lateral aspect of talus

• hinge joint

ligaments

• deltoid ligament

• lateral ligament

• anterior and posterior tibiofibular ligament

joints of foot

4 types of diarthroses

1. intertarsal joint

2. tarsometatarsal joint

3. metatarsophalangeal (MP) joint

4. interphalangeal (IP) joint

intertarsal joint

plane joint between tarsals

tarsometatarsal joint

plane joint between distal tarsal bone and metatarsals

metatarsophalangeal joint

between metatarsal and proximal phalanges

• condylar joint

interphalangeal joint

hinge joint between phalanges

arthritis

broad term for inflammation of joints

bursitis

inflammation of bursa

• usually due to overuse of a joint

dislocation

displacement of bone from normal position at a joint

• most common at fingers, thumbs, shoulder, knee

gout

• uric acid crystals accumulate in joints and irritate articular cartilage and synovial membrane

  • swelling and pain

  • tissue degeneration

  • sometimes fusion of joint

• most commonly affect great toe

rheumatism

broad term for any pain including bones, ligaments, tendons, muscles

sprain

torn ligaments

• sometimes with damage to a meniscus or other cartilage

strain

painful overstretching of a tendon or muscle without serious tissue damage

• often results from inadequate warm-up before exercise

synorvitis

inflammation of a joint capsule

• often as a complication of a sprain

tendinitis

a form of bursitis in which a tendon sheath is inflamed

flexion

decreases angle of joint

extension

increases angle of joint

hyperextension

extends beyond anatomical position angle of joint and/or causes injury

abduction

movement away from midline of body

adduction

movement toward midline of body

elevation

raises body part vertically

depression

lowers body part

protraction

anterior movement of body part

retraction

posterior movement of body part

circumduction

distal end of limb or digit moves in a circle

pronation

radius and ulna end up crossed; palms turned posteriorly

supination

radius and ulna end up parallel; palms turned anteriorly

opposition

thumb and finger meet together

dorsiflexion

dorsum of foot is brought towards to anterior surface of leg

plantar flexion

sole of foot is brought towards to posterior surface of leg

inversion

turns the sole medially or inward

eversion

turns the sole laterally or outward

ball and socket joint

round head of one bone rest within cup shape bone

• movement in all directions

• multiaxial

example:

• glenohumeral joint

• hip joint

plane joint

flattened face slide across one another

• sliding movement

• biaxial

example:

• intercarpal joints

• intertarsal joints

hinge joint

convex feature of one bone fits into concave of bone

• movement in one direction like door

• monaxial

examples:

• elbow joint

• knee joint

pivot joint

bone with round surface fits into ring form by ligament and/or another bone

• rotation on single axis

• monaxial

example:

• atlantoaxial joint

• atlas and axis vertebrae

• radius and ulna

saddle joint

saddle shape surfaces

• movement back and forth, side to side

• biaxial

example:

• thumb (carpometacarpal joint)

condylar joint

oval surfaces

• movement in two planes with no rotation

• biaxial

examples:

• metacarpophalangeal

lateral rotation

limb or body move away from midline longitudinally

medial rotation

limb or body move toward midline longitudinally

lateral flexion

vertebral column bends in lateral direction

humeroulnar joint

between trochlea of humerus and trochlear notch of ulna

• hinge joint

• flexion and extension of forearm

humeroradial joint

between capitulum of humerus and head of radius

• hinge joint

• flexion and extension

radioulnar joint

between head of radius and radial notch of ulna

• pivot joint

• pronation and supination