chapter 9 joints of the body classification - bony, fibrous, cartilaginous synovial(diarthrosis) movement and levers selected diarthrosis joints

a couple of terms joint = an area where bones meet arthrology = study of structure, function, & dysfunction of joints kinesiology = study of musculoskeletal movement biomechanics = study of movements, physics, physiology of joints tendon = tough collagenous CT which joins a muscle to a bone ligament = tough collagenous CT which joins a bone to a bone bursa = fibrous sac filled with synovial fluid which protects tissues articular disc = fibrocartilage which absorbs shock in joints meniscus = as above but in knees

lots of terms flexion. extension. hyperextension abduction. adduction lots of terms flexion extension hyperextension abduction adduction elevation depression protraction retraction circumduction rotation medial(internal) rotation lateral(external) rotation supination pronation opposition reposition dorsiflexion plantar flexion inversion eversion excursion range of motion axis of rotation degrees of freedom

more terms symphysis. fulcrum. resistance effort. multiaxial more terms symphysis fulcrum resistance effort multiaxial biaxial monaxial condyle dens fossa labrum fovea epicondyle tuberosity malleolus calcaneal

bony joint = synostosis = immobility fibrous joint (synarthrosis) = sutures, gomphosis, syndesmosis

sutures immobile or slightly mobile serrate (dovetail), lap (miter), plane (butt) gomphosis = held in place by collagen syndesmosis = fibrous joint over distance (radius/ulna)

cartilaginous joints (amphiarthrosis) synchondroses = bones bound by hyaline cartilage symphysis = bones joined by fibrocartilage synovial (diarthrosis) = most common & complicated very mobile to limited mobility

synovial (diarthrosis) joints most common, most complicated vary from freely mobile to limited mobility

joints are equivalent to levers from the point of view of biomechanics joints act as hammers, screw drivers, wheel barrows,

mechanical advantage the function of a lever is to provide a benefit when a force is used to move an object a wedge allows you to use 80 pounds of force to push a 400 pound box 6 feet up into a truck you may use 80 pounds of force to quickly lift 60 pounds of ice each type of lever provides an advantage the benefit may be a reduced effort or increased speed

a mechanical advantage greater than one means the lever produces more force than was put in but less speed or distance a mechanical advantage less than one means the lever produced less force than was used but generated more speed or distance moved

body joints allow for many types of movements and they each have a distinct name most joints are able to perform two movements and some can perform more than two movements

the text briefly describes six synovial joints but within the brief description are many names of muscles, bones, bony projections, ligaments, bursa, tendons coordinate what you learn with the lab you can learn more but you must learn the ones tested in the lab

TMJ (jaw) joint the condyle of the mandible interacts with the mandibular fossa of the temporal bone held in place by the sphenomandibular & lateral ligament the joint consists of a depression into the temporal bone with a synovial membrane, articular disc, and a cavity to accept the condyle ar the jaw is moved open your mouth to accept food or ….. yawn or yell ouch or yell awesome

shoulder joint (glenohumeral, humeroscapular) shallow joint – loose joint – much movement – multiaxial BUT stability sacrificed multiple bony surfaces, ligaments, & tendons

the shoulder is stabilized anteriorly by the biceps brachii muscle tendon forcing the humeral head into the glenoid cavity the supraspinatus infraspinatus, teres minor, and subscapularis muscles stabilize the joint and their tendons form the rotator cuff five ligaments also stabilize the joint the glenohumeral, coracohumeral, & transverse humeral four bursae are present subdeltoid, subacromal, suncoracoid, and subscapular

elbow joint hinge – 2 articulations – humeroulnar joint – humeroradial joint

hip (coxal) joint pelvis – acetabulum – deep socket very stable – acetabular labrum(fibrocartilage) – fovea capitis iliofemoral, pubofemoral ligaments anteriorly ischiofemoral ligament posteriorly transverse acetabular ligament helps hold the labrum in place

knee (tibiofemoral)joint largest – most complex – hinge + gliding + rotation – the joint capsule involves the lateral & posterior aspects of the knee – main stabilization is by the quadriceps tendon in front and the semimembranosus tendon at the rear two C shaped cartilages the lateral and medial menisci joined by a transverse ligament absorbs shock

posteriorly (popliteal) extracapsular and intracapsular ligaments extra = fibular(lateral) & tibial(medial) collateral ligaments intra = X – anterior & posterior cruciate ligaments (attach to tibia) 13 bursae = 4 anterior = superficial infrapatellar, suprapatellar, prepatellar, deep infrapatellar – 2 posterior = semimembranous and popliteal bursa – and 7 on the lateral and medial surfaces

the patella patella & patellar ligament form patellofemoral joint

ankle (talocrural) joint two articulations – tibia and talus (medial) – fibula and talus (lateral) many ligaments – many bones