Summary - Joints (Ch8).pdf PDF

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SHS111 topic summaries- detailed, comprehensive and organised notes covering content from lectures, tutorials, practicals, textbooks and further research. High quality, easy-to-read notes for easy reference and study. Student achieved high marks in subject....

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CH#8#JOINTS$ # What$are$joints?$ Articulation#–#a#site#where#two#or#more#bones#meet# # Functions:$ • Give#skeleton#mobility$ • Hold#skeleton#together$ $ CLASSIFICATION$OF$JOINTS$ • Classified#by#structure#and#by#function# • Structural#classification:# ? Based#on#material#binding#bones#together#and#whether#or#not#a#joint#cavity#is#present# ? Three#structural#classifications:# à฀#Fibrous# à฀#Cartilaginous# à฀#Synovial# • Functional#classification:# ? Based#on#amount#of#movement#allowed#by#the#joint# ? Three#functional#classifications:# à฀#Synarthrotic#–#immovable# à฀#Amphiarthrotic#–#slightly#movable# à฀#Diarthrotic#–#freely#movable# # When#classifying#bones#à฀#structure#first#then#movement# #

Fibrous$Joints:$$ # • • •

Bones#are#joined#by#fibrous$tissue#(namely#dense#fibrous#connective#tissue)# No#joint#cavity# Most#are#synarthrotic#(immovable)#

# Three#types#?# Sutures:$ • Occur#only#between#bones#of#the#skull# • Rigid,#interlocking#joints## • Bones#connected#by#short#connective#tissue#fibres# • Allow#for#growth#during#childhood# • During#middle#age,#sutures#ossify#(closed#sutures#are#called#synostoses)# • Immovable#nature#of#sutures#is#used#for#protection# $ Syndesmoses:$ • Bones#are#connected#by#ligaments# • Movement#varies#from#immovable#to#slightly#movable# • Examples:#synarthrotic#tibiofibular#joint,#diarthrotic#interosseous#connection#between#radius#and#ulna# $ Gomphoses:$ • Peg?in?socket#joints#of#teeth#in#alveolar#sockets# • Fibrous#connection#is#the#periodontal$ligament#

SHS111$Anatomy$&$Physiology$I$4$1$

Cartilaginous$Joints:$ • •

Bones#united#by#cartilage# No#joint#cavity#

# Two#types#–# Synchondroses:$ • Bar#or#plate#of#hyaline#cartilage#unites#bones# • All#are#synarthrotic# • Example:#epiphyseal#plates#in#the#long#bones#of#children#(temporary#joints#that#eventually#become#synostoses),# immovable#joint#between#costal#cartilage#of#first#rib#and#the#manubrium#of#the#sternum# # # # # # # # # # # # # Symphyses:# • Hyaline#cartilage#covers#the#articulating#surfaces#and#is#fused#to#an#intervening#pad#of#fibrocartilage# • Strong,#flexible# • Amphiartrotic#(slightly#movable)# • Examples:#pubic#symphysis,#intervertebral#joints# # # # # # # # # # # # hysiology$I$4$2$

Synovial$Joints:$$ • •

All#are#diarthrotic#(freely#movable)# Include#all#limb#joints#and#most#joints#of#the#body#

# Distinguishing$features:$ 1. Articular$cartilage:#hyaline#cartilage# 2. Joint$(synovial)$cavity:#small#potential#space#inside#capsule,#full#of# synovial#fluid# 3. Articular$(joint)$capsule$(all#connective#tissue#that#surrounds#the# joint):# à฀#Outer#fibrous(capsule#of#dense#irregular#connective#tissue# à฀#Inner#synovial(membrane#of#loose#connective#tissue#(lines#fibrous# capsule#internally#and#covers#all#joint#surfaces#that#are#not#covered# in#hyaline#cartilage)# 4. Synovial$fluid:# à฀#Viscous#slippery#filtrate#of#plasma#and#hyaluronic#acid# à฀#Lubricates#(reduces#friction)#and#nourishes#articular#cartilage# 5. Reinforcing#ligaments:# à฀#capsular#(intrinsic)#–#part#of#the#capsule#(eg.#medial# collateral#ligament#in#knee)# à฀#intracapsular#–#inside#capsule#(eg.#ACL#in#knee)# à฀#extracapsular#–#outside#capsule#(eg.#lateral#collateral#ligament#on#lateral#side#of#knee)# 6. Rich#nerve#and#blood#vessel#supply:# à฀#Nerve#fibres#detect#pain,#monitor#joint#position#and#stretch# à฀#Capillary#beds#produce#filtrate#for#synovial#fluid# # Other$features$of$some$synovial$joints:$ • Fatty$pads:#pocket#of#fat#for#extra#protection#(between#the#fibrous#capsule#and#the#synovial#membrane)# • Articular$discs:#fibrocartilage#separating#the#articular#surfaces#(menisci).##They#improve#the#fit#between#articulating# bone#ends,#making#the#joint#more#stable.#(occur#in#knee,#jaw#and#a#few#other#joints)# # Friction4reducing$structures:$ Bursae:$ • flattened,#fibrous#sacs#lined#with#synovial#membranes# • contain#synovial#fluid# • act#as#‘ball#bearings’# • occur#where#ligaments,#muscles,#skin,#tendons,#or#bones#rub#together# Tendon$sheath:# • an#elongated#bursa#that#wraps#completely#around#a#tendon#subjected#to#friction# • common#where#several#tendons#are#crowded#together#within#narrow#canals# # # # # # # # # # # # # # # # # # # $ SHS111$Anatomy$&$Physiology$I$4$3$

$ $ Stabilizing$factors$at$synovial$joints:$ • Shape&of&articular&surface#(minor#role)#?#Eg.#the#ball#and#deep#socket#of#the#hip#joint#is#extremely#stable)$ • Ligaments#number#and#location#(limited#role)#–#prevent#excessive#and#undesirable#motion#(but#ligaments#can#only# stretch#about#6%#of#their#length#before#they#snap)$ • Muscle&tone#(keep#tendons#that#cross#the#joint#taut)#–#most#important#stabilizing#factor,#extremely#important#in# stabilizing#the#shoulder#and#knee#joints#and#arches#of#the#foot.$ $ Movements$allowed$by$synovial$joints:$ Muscle#attachments#across#a#joint:# • Origin:$attachment#to#the#immovable#bone$ • Insertion:#attachment#to#the#movable#bone$ (muscles#contraction#causes#the#insertion#to#move#toward#the#origin)# • Movement#occurs#along#transverse,#frontal#and#sagittal#planes# • Range#of#motion:# à฀#nonaxial$movement#–#slipping#movements#only#(eg.#ribs#to#vertebrae)# à฀#uniaxial$movement#–#movement#in#one#plane# à฀#biaxial$movement#–#movement#in#two#planes# à฀#multiaxial$movement#–#movement#in#or#around#all#three#planes# • Three#general#types#of#movements:# Gliding$movements:$ à฀#Simplest#joint#movement# à฀#Occurs#when#one#flat,#or#nearly#flat,#bone#surface#glides#or#slips#over#another#without#appreciable# angulation#or#rotation# à฀#Example:#intercarpal#and#intertarsal#joints,#between#flat#articular#processes#of#the#vertebrae# Angular$movements:$ à฀#Increase#or#decrease#the#angle#between#two#bones# à฀#May#occur#in#any#plane#of#the#body# à฀#Include# flexion#(decreases#angle#of#the#joint)# extension#(increases#angle#of#the#joint)# hyperextension#(excessive#extension#beyond#anatomical#position)# abduction#(moving#limb#away#from#midline#of#body)# adduction#(moving#limb#towards#midline#of#body)# circumduction#(moving#a#limb#so#that#it#describes#a#cone#in#space)# Rotation:$ à฀#Turning#of#a#bone#around#its#own#long#axis# à฀#Medial#and#lateral#rotation# à฀#Example:#between#C1#and#C2#vertebrae,#rotation#of#humerus#and#femur# • Special#types#of#movement:# à฀#Supination:#palm#facing#anteriorly#or#superiorly#(palm#facing#up,#holding#a#cup#of#soup)# # NOTE:#hand#is#supinated#in#the#anatomical#position# à฀#Pronation:#palm#faces#posteriorly#or#inferiorly#(palm#facing#down,#radius#crosses#ulna)# # # # # # NOTE:#pronation#and#supination#refers#to#the#movement#of#the#radius#around#the#ulna# à฀#Dorsiflexion:#flexing#foot# à฀#Plantar$flexion:#pointing#foot# à฀#Inversion:#sole#of#the#foot#turns#in#medially# à฀#Eversion:#sole#of#the#foot#turns#out#laterally# # # à฀#Protraction:#nonangular#anterior#movements#in#the#transverse#plane#(eg.#pushing#jaw#out)# # # à฀#Retraction:#nonangular#posterior#movements#in#the#transverse#plane#(eg.#pulling#jaw#in)# # # # à฀#Elevation:#lifting#a#body#part#superiorly#(eg.#scapula#is#elevated#when#you#shrug#your#shoulders)# à฀#Depression:#moving#the#elevated#part#inferiorly#(eg.#when#chewing,#mandible#is#elevated#then# depressed)# à฀#Oppostion:#this#movement#is#the#action#when#you#touch#your#thumb#to#the#tips#of#the#other#fingers#on# the#same#hand# # Types$of$Synovial$Joints$ • Plane$joints:#articular#surfaces#are#essentially#flat#and#they#allow#only#short#nonaxial#gliding#movements#(eg.#gliding# joints)# SHS111$Anatomy$&$Physiology$I$4$4$

• • • •

• # $$

Hinge$joints:#motion#is#along#a#single#plane#(uniaxial)#and#permits#flexion#and#extension#only#(eg.#elbow,#knee,# interphalangeal#joints)# Pivot$joints:#only#movement#allowed#is#uniaxial#rotation#of#one#bone#around#its#own#long#axis#(eg.#the#joint# between#the#atlas#and#dens#of#the#axis)# Condyloid$joints:#the#oval#articular#surface#of#one#bone#fits#into#a#complementary#depression#in#another#(eg.# radiocarpal#(wrist)#joints#and#the#metacarpophalangeal#(knuckle)#joints)# Saddle$joints:$resemble#condyloid#joints#but#they#allow#greater#freedom#of#movement.##Each#articular#surface#has# both#concave#and#convex#areas.##These#articular#surfaces#fit#together,#concave#to#convex#surfaces.#(Eg.# carpometacarpal#joints#of#the#thumbs)$ Ball4and4socket$joints:$the#spherical#or#hemispherical#head#of#one#bone#articulates#with#the#cuplike#socket#of# another#(multiaxial.#Eg.#shoulder#and#hip)# $

SHS111$Anatomy$&$Physiology$I$4$5$

Specific$synovial$joints:$ $ Knee$Joint:$ • Largest,#most#complex#joint#of#body# • Three#joints#surrounded#by#a#single#joint#cavity:# ? Femoropatellar$joint#(plane#joint,#allows#gliding#motion#during#knee#flexion)# ? Lateral$and$medical$joints#(collectively#known#as#the#tibiofemoral#joints#à฀#between#the#femoral# condyles#and#the#lateral#and#medial#menisci#of#the#tibia)# • Hinge#joint#(flexion#and#extension#however#some#rotation#is#possible#when#the#knee#is#partly#flexed)# • Its#joint#cavity#is#only#partially#enclosed#by#a#capsule#(articular#capsule#present#on#the#sides#and#posterior#aspects#of# the#knee).##Anteriorly,#where#the#capsule#is#absent,#three#broad#ligaments#run#from#the#patella#to#the#tibia#below# (patellar$ligament,#medical$patellar$reticulum#and#lateral$patellar$reticulum)# • At#least#12#associated#bursae# • Capsule#is#reinforced#by#muscle#tendons# • Capsular#and#extracapsular#ligaments:# ? Extracapsular#fibular#and#tibial#collateral#ligaments# ? Capsular#oblique#popliteal#ligament# # # #########help#prevent#hyperextension# ? Capsular#arcuate#popliteal#ligament# • Intracapsular#ligaments:# ? ACL#and#PCL# ? Prevent#anterior?posterior#displacement# ? Reside#outside#the#synovial/joint#cavity# • The#knee#can#absorb#a#vertical#force#equal#to#seven#times#body#weight#but#it#is#very#vulnerable#to#horizontal#blows# (eg.#during#tackling#in#football#and#ice#hockey)# # # #

SHS111$Anatomy$&$Physiology$I$4$6$

I$4$7$

#

Shoulder$(Glenohumeral)$joint:$ • • •

•

•

Ball?and?socket#joint#(head#of#humerus#and#glenoid#cavity#of#the#scapula)# Stability#sacrificed#for#greater#freedom#of#movement# Reinforcing#ligaments:# ? Coracohumeral#ligament#(from#coracoid#process#to#humerus#–#helps#support#weight#of#upper#limb)# ? Three#glenohumeral#ligaments#(from#glenoid#cavity#to#humerus#–#somewhat#weak#anterior# reinforcements)# Reinforcing#muscle#tendons:# ? Cross#the#shoulder#joint# ? Tendon#of#the#long#head#of#the#biceps#brachii#muscle#(secures#the#humerus#to#the#glenoid#cavity;#runs# in#the#intertubercular#sulcus#of#the#humerus)# ? Rotator#cuff#tendons#(and#associated#muscles)#–#subscapularis,#supraspinatus,#infraspinatus,#teres# minor# Shoulder#reinforcements#are#weakest#anteriorly#and#inferiorly#

#

# #

#

SHS111$Anatomy$&$Physiology$I$4$8$

Elbow$Joint:$ • • • • • •

Radius#and#ulna#articulate#with#the#humerus# Hinge#joint#–#formed#mainly#by#trochlear#notch#of#ulna#and#trochlear#of#humerus# Hook#into#olecranon#fossa# Flexion#and#extension#only# Anular#ligament#–#wraps#entirely#around#head#of#radius# Two#capsular#ligaments#restrict#side?to?side#movement:# ? Ulnar#collateral#ligament# ? Radial#collateral#ligament#

#

# #

#

SHS111$Anatomy$&$Physiology$I$4$9$

Hip$(Coxal)$Joint:$ • • • •

• •

Ball?and?socket#(head#of#femur#in#acetabulum)# Good#range#of#motion,#but#limited#by#deep#socket# Acetabular#labrum#–#enhances#depth#of#socket# Reinforcing#ligaments:# ? Iliofemoral#ligament#(ilium#to#femoral#–#V?shaped#ligament#anteriorly)# ? Pubofemoral#ligament#(pubis#to#femur#–#triangular#thickening#of#the#inferior#part#of#the#capsule)# ? Ischiofemoral#ligament#(ischium#to#femur#–#spiralling#posterior#ligament)# ? Ligamentum#teres#(ligament#of#the#head#of#the#femur)# Articular#capsule#completely#encloses#joint# Stability#comes#mainly#from#the#deep#socket#

#

# #

#

SHS111$Anatomy$&$Physiology$I$4$10$

COMMON$JOINT$INJURIES$ $ • Sprains# ? Ligaments#are#stretched#or#torn# ? Partial#tears#slowly#repair#themselves# ? Complete#ruptures#need#surgery# ? Common#sprain#sites#–#lumbar#region,#the#ankle,#the#knee# • Cartilage#tears# ? Due#to#compression#and#sheer#stress# ? Fragments#may#cause#joint#to#lock#or#bind# ? Cartilage#rarely#repairs#itself#because#it#is#avascular#and#can’t#obtain#enough#nourishment# ? Repaired#by#arthroscopic#surgery# ? most#cartilage#injuries#involve#tearing#of#the#knee#menisci# • Dislocations# ? Occurs#when#bones#forced#out#of#alignment# ? Accompanied#by#sprains,#inflammation#and#joint#immobilization# ? Caused#by#serious#falls#or#playing#sports# ? Subluxation:#partial#dislocation#of#a#joint# # INFLAMMATORY$AND$DEGENERATIVE$CONDITIONS$ # • Bursitis# ? Inflammation#of#a#bursa,#usually#caused#by#a#blow#or#friction#(overuse)# ? Treated#with#rest#and#ice#and,#if#severe,#anti?inflammatory#drugs# • Tendonitis# ? Inflammation#of#tendon#sheaths# ? Caused#by#overuse# ? Symptoms#–#pain#and#swelling# ? Treatment#–#rest,#ice,#anti?inflammatory#drugs# • Arthritis# ? Describes#over#100#different#types#of#inflammatory#or#degenerative#diseases#that#damage#the#joints# ? Most#widespread#crippling#disease#in#the#US# ? Symptoms:#pain,#stiffness,#swelling#of#the#joint# ? Acute#forms:#result#from#bacterial#invasion,#treated#with#antibiotics# ? Chronic#forms:#include#osteoarthritis,#rheumatoid#arthritis,#gouty#arthritis# # Osteoarthritis$(OA):# ? Common,#irreversible,#degenerative#(wear?and?tear)#arthritis# ? More&cartilage&is&destroyed&then&replaced& ? 85%#of#all#Americans#get#it,#more#women#than#men# ? Probably#related#to#the#normal#aging#process# ? Articular#cartilages#are#eroded:#exposed#bone#ends#thicken,#enlarge,#form#bone#spurs,#and#restrict# movement# ? Treatment:#moderate#activity,#mild#pain#relievers,#capsaicin#creams,#glucosamine,#chondroitin#sulfate# # Rheumatoid$arthritis$(RA):$ ? Chronic,#inflammatory,#autoimmune#disease#of#unknown#cause# ? Usually#arises#between#age#40#and#50,#but#may#occur#at#any#stage;#affects#3#times#as#many#women#as# men# ? Signs#and#symptoms:#joint#pain,#swelling#(usually#bilateral#–#so#if#right#elbow#is#affected,#left#elbow#will# also#be#affected),#anaemia,#osteoporosis,#muscle#weakness,#and#cardiovascular#problems# ? Autoimmune#disease#–#a#disorder#where#the#body’s#immune#system#attacks#its#own#tissues# ? Begins#with#synovitis#(inflammation#of#the#synovial#membrane#–#part#of#articular#capsule)#of#the# affected#joint# ? Inflammatory#blood#cells#migrate#to#the#joint,#release#inflammatory#chemicals# ? Inflamed#synovial#membrane#thickens#into#a#pannus#(an#abnormal#tissue#that#clings#to#the#articular# cartilages)# ? Pannus#erodes#cartilage,#scar#tissue#forms,#articulating#bone#ends#connect#(ankylosis)#

SHS111$Anatomy$&$Physiology$I$4$11$

?

Treatment:#pendulum#swinging#from#conservative#RA#therapy#utilizing#aspirin,#long?term#antibiotic# therapy,#and#physical#therapy#to#a#more#progressive#treatment#course#using#immune?suppressants# such#as#methotrexate,#or#anti?inflammatory#drugs.#

SHS111$Anatomy$&$Physiology$I$4$12$...