accessory ligaments

7/23/2019 Accessory Ligaments

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Factors Afecting Contactand Range o Motionat Synovial JointsO B J E C T I V E

Describe six actors that inuence the tye o !ove!entand range o !otion ossible at a synovial "oint#

$he articular suraces o synovial "oints contact one anotherand deter!ine the tye and ossible range o !otion# Range ofmotion (ROM) reers to the range% !easured in degrees o acircle% through &hich the bones o a "oint can be !oved# $he ollo&ingactors contribute to 'eeing the articular suraces in contactand afect range o !otion(1. Structure or shape of the articulating bones. $he structure orshae o the articulating bones deter!ines ho& closely theycan )t together# $he articular suraces o so!e bones have aco!le!entary relationshi# $his satial relationshi is veryobvious at the hi "oint% &here the head o the e!ur articulates&ith the acetabulu! o the hi bone# An interloc'ing )tallo&s rotational !ove!ent#2. Strength and tension (tautness) of the joint ligaments. $hediferent co!onents o a )brous casule are tense or taut only&hen the "oint is in certain ositions# $ense liga!ents not onlyrestrict the range o !otion but also direct the !ove!ent o thearticulating bones &ith resect to each other# *n the 'nee "oint%or exa!le% the anterior cruciate liga!ent is taut and the osteriorcruciate liga!ent is loose &hen the 'nee is straightened%and the reverse occurs &hen the 'nee is bent# *n the hi "oint%certain liga!ents beco!e taut &hen standing and !ore )r!lyattach the head o the e!ur to the acetabulu! o the hi bone#3.Arrangement and tension of the muscles. Muscle tension reinorcesthe restraint laced on a "oint by its liga!ents% andthus restricts !ove!ent# A good exa!le o the efect o!uscle tension on a "oint is seen at the hi "oint# +hen thethigh is exed &ith the 'nee extended% the exion o the hi"oint is restricted by the tension o the ha!string !uscles onthe osterior surace o the thigh% so !ost o us can,t raise astraightened leg !ore than a -./degree angle ro! the oor#0ut i the 'nee is also exed% the tension on the ha!string!uscles is lessened% and the thigh can be raised arther% allo&ingyou to raise your thigh to touch your chest#4. Contact of soft parts.$he oint at &hich one body surace

contacts another !ay li!it !obility# For exa!le% i you bendyour ar! at the elbo&% it can !ove no arther ater the anteriorsurace o the orear! !eets &ith and resses against thebices brachii !uscle o the ar!# Joint !ove!ent !ay also berestricted by the resence o adiose tissue#5. Hormones.Joint exibility !ay also be afected by hor!ones#For exa!le% relaxin% a hor!one roduced by the lacenta and

ovaries% increases the exibility o the )brocartilage o theubic sy!hysis and loosens the liga!ents bet&een thesacru!% hi bone% and coccyx to&ard the end o regnancy#$hese changes er!it exansion o the elvic outlet% &hich

assists in delivery o the baby#6. Disuse. Move!ent at a "oint !ay be restricted i a "oint has not


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been used or an extended eriod# For exa!le% i an elbo&"oint is i!!obili1ed by a cast% range o !otion at the "oint !aybe li!ited or a ti!e ater the cast is re!oved# Disuse !ay alsoresult in decreased a!ounts o synovial uid% di!inishedexibility o liga!ents and tendons% and muscular atrophy, areduction in si1e or &asting o a !uscle#CHECKOI!T22# 3o& do the strength and tension o liga!entsdeter!ine range o !otion4

-#5 Selected Joints o the 0odyO B J E C T I V E

*dentiy the !a"or "oints o the body by location%classi)cation% and !ove!ents#

*n Chaters 6 and 5% &e discussed the !a"or bones and their !ar'ings#*n this chater &e have exa!ined ho& "oints are classi)edaccording to their structure and unction% and &e have introducedthe !ove!ents that occur at "oints#$able -#7 8selected "oints othe axial s'eleton9 and$able -#: 8selected "oints o the aendicular

s'eleton9 &ill hel you integrate the inor!ation you havelearned in all three chaters# $hese tables list so!e o the !a"or"oints o the body according to their articular co!onents 8thebones that enter into their or!ation9% their structural and unctionalclassi)cation% and the tye8s9 o !ove!ent that occur8s9 ateach "oint#;ext &e exa!ine in detail several selected "oints o the body ina series o exhibits#


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the synovial cavity into suerior and inerior co!art!ents%each &ith a synovial !e!brane 8Figure -#22c9#

2.Articular capsule.$hin% airly loose enveloe around the circu!erenceo the "oint 8Figure -#22a% b9#3. Lateral ligament.$&o short bands on the lateral surace o

the articular casule that extend ineriorly and osteriorlyro! the inerior border and tubercle o the 1ygo!atic rocesso the te!oral bone to the lateral and osterior asect othe nec' o the !andible# $he lateral liga!ent is covered bythe arotid gland and hels strengthen the "oint laterally andrevent dislace!ent o the !andible 8Figure -#22a9#4. Sphenomandibular ligament 8se/no/!an/D*0/u/lar9# $hinband that extends ineriorly and anteriorly ro! the sine o theshenoid bone to the ra!us o the !andible 8Figure -#22b9# *tdoes not contribute signi)cantly to the strength o the "oint#5. Stylomandibular ligament 8st/lo/!an/D*0/u/lar9# $hic'enedband o dee cervical ascia that extends ro! the styloid

rocess o the te!oral bone to the inerior and osteriorborder o the ra!us o the !andible# $his liga!ent searatesthe arotid gland ro! the sub!andibular gland and li!its!ove!ent o the !andible at the $MJ 8Figure -#22a% b9#

Moement-*n the te!oro!andibular "oint% only the !andible !oves becausethe te!oral bone is )r!ly anchored to other bones o the s'ull bysutures# Accordingly% the !andible !ay unction in deression8"a& oening9 and elevation 8"a& closing9% &hich occurs in the ineriorco!art!ent% and rotraction% retraction% lateral dislace!ent%and slight rotation% &hich occur in the suerior co!art!ent8see Figure -#-a@d9#

Shoulder Joint

"e#nition$he -/o&e% *oint is a ball/and/soc'et "oint or!ed by the head othe hu!erus and the glenoid cavity o the scaula# *t is also reerredto as the humeroscapular or glenohumeral joint 8gle/no/3E/!er/al9#

+natomi,a Com$onent-1.Articular capsule.$hin% loose sac that co!letely envelosthe "oint and extends ro! the glenoid cavity to the anato!icalnec' o the hu!erus# $he inerior art o the casule is its&ea'est area 8Figure -#2?9#2. Coracohumeral ligament 8'orB/a/'o/3E /!er/al9# Strong% broadliga!ent that strengthens the suerior art o the articular casuleand extends ro! the coracoid rocess o the scaula tothe greater tubercle o the hu!erus 8Figure -#2?a% b9# $heliga!ent strengthens the suerior art o the articular casuleand reinorces the anterior asect o the articular casule#

3. Glenohumeral ligaments# $hree thic'enings o the articularcasule over the anterior surace o the "oint that extendro! the glenoid cavity to the lesser tubercle and anato!ical


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nec' o the hu!erus# $hese liga!ents are oten indistinct orabsent and rovide only !ini!al strength 8Figure -#2?a% b9#$hey lay a role in "oint stabili1ation &hen the hu!erus aroachesor exceeds its li!its o !otion#4. rans!erse humeral ligament. ;arro& sheet extending ro!the greater tubercle to the lesser tubercle o the hu!erus

8Figure -#2?a9# $he liga!ent unctions as a retinaculu!8retaining band o connective tissue9 to hold the long head othe bices brachii !uscle#5. Glenoid labrum. ;arro& ri! o )brocartilage around the edgeo the glenoid cavity that slightly deeens and enlarges theglenoid cavity 8Figure -#2?b% c9#6. "ursae. Four bursae 8see Section -#:9 are associated &ith theshoulder "oint# $hey are the subscapular bursa 8Figure -#2?a9%subdeltoid bursa, subacromial bursa 8Figure -#2?a@c9% andsubcoracoid bursa#

Moement-$he shoulder "oint allo&s exion% extension% hyerextension%abduction% adduction% !edial rotation% lateral rotation% and circu!ductiono the ar! 8see Figures -#@-#59# *t has !ore reedo!o !ove!ent than any other "oint o the body# $his reedo!results ro! the looseness o the articular casule and theshallo&ness o the glenoid cavity in relation to the large si1e othe head o the hu!erus#Although the liga!ents o the shoulder "oint strengthen it toso!e extent% !ost o the strength results ro! the !uscles thatsurround the "oint% esecially the rotator cuf muscles.$hese!uscles 8surasinatus% inrasinatus% teres !inor% and subscaularis9anchor the hu!erus to the scaula 8see also Figure 22#29#

$he tendons o the rotator cuf !uscles encircle the "oint 8excetor the inerior ortion9 and inti!ately surround the articularcasule# $he rotator cuf !uscles &or' as a grou to hold thehead o the hu!erus in the glenoid cavity#


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extends ro! the lateral eicondyle o the hu!erus to the anularliga!ent o the radius and the radial notch o the ulna8Figure -#27b9#4.Anular ligament of the radius. Strong band that encircles thehead o the radius# *t holds the head o the radius in the radialnotch o the ulna 8Figure -#27a% b9#

Moement-$he elbo& "oint allo&s exion and extension o the orear! 8seeFigure -#c9#

3i Joint

"e# nition$he /i$ *oint (coxal joint) is a ball/and/soc'et "oint or!ed by

the head o the e!ur and the acetabulu! o the hi bone#

+natomi,a Com$onent-1.Articular capsule. Gery dense and strong casule that extendsro! the ri! o the acetabulu! to the nec' o the e!ur8Figure -#2:c9# +ith its accessory liga!ents% this is one o thestrongest structures o the body# $he articular casule consistso circular and longitudinal )bers# $he circular )bers% calledthe 1ona orbicularis% or! a collar around the nec' o the e!ur#Accessory liga!ents 'no&n as the ilioemoral ligament,

puboemoral ligament, and ischioemoral ligament reinorce

the longitudinal )bers o the articular casule#2. %liofemoral ligament 8ilB/e/o/F


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. rans!erse ligament of the acetabulum. Strong liga!ent thatcrosses over the acetabular notch# *t suorts art o the acetabularlabru! and is connected &ith the liga!ent o the heado the e!ur and the articular casule 8Figure -#2:c9#

Moement-$he hi "oint allo&s exion% extension% abduction% adduction%lateral rotation !edial rotation% and circu!duction o the thigh8see Figures -#@-#59# $he extre!e stability o the hi "oint isrelated to the very strong articular casule and its accessory liga!ents%the !anner in &hich the e!ur )ts into the acetabulu!%and the !uscles surrounding the "oint# Although the shoulder andhi "oints are both ball/and/soc'et "oints% the hi "oints do nothave as &ide a range o !otion# Flexion is li!ited by the anteriorsurace o the thigh co!ing into contact &ith the anterior abdo!inal&all &hen the 'nee is exed and by tension o the ha!string!uscles &hen the 'nee is extended#


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o the "oint# osterior surace o the liga!ent is searatedro! the synovial !e!brane o the "oint by an inraatellar atad 8Figure -#2c@e9#4. bliue popliteal ligament 8o/H*$/e/al9# 0road% at liga!entthat extends ro! the intercondylar ossa and lateralcondyle o the e!ur to the head and !edial condyle o the

tibia 8Figure -#2% h9# $he liga!ent strengthens the osteriorsurace o the "oint#5.Arcuate popliteal ligament. e!ale hor!ones that allo& or greater exibilityo liga!ents% !uscles% and tendons but &hich do not er!itthe! to absorb the stresses ut on the!% thus transerring thestresses to the ACH> and e!ales, lesser !uscle strength causingthe! to rely !ore on the ACH to hold the 'nee in lace#'. &osterior cruciate ligament (&CL).


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is exed# $his is very i!ortant &hen &al'ing do&n stairsor a stee incline#.Articular discs (menisci).$&o )brocartilage discs bet&eenthe tibial and e!oral condyles hel co!ensate or the irregularshaes o the bones and circulate synovial uid#a. 'edial meniscus. Se!icircular iece o )brocartilage

8C/shaed9# *ts anterior end is attached to the anterior intercondylarossa o the tibia% anterior to the anterior cruciate liga!ent#*ts osterior end is attached to the osterior intercondylarossa o the tibia bet&een the attach!ents o the osteriorcruciate liga!ent and lateral !eniscus 8Figure -#2a% b% d% h9#'. Lateral meniscus. ;early circular iece o )brocartilage8aroaches an inco!lete K in shae9 8Figure -#2a% b% d% h9#*ts anterior end is attached anteriorly to the intercondylare!inence o the tibia% and laterally and osteriorly to the

anterior cruciate liga!ent# *ts osterior end is attachedosteriorly to the intercondylar e!inence o the tibia% and

anteriorly to the osterior end o the !edial !eniscus# $heanterior suraces o the !edial and lateral !enisci are connectedto each other by the transverse ligament o the knee8Figure -#2a9 and to the !argins o the head o the tibia bythe coronary ligaments 8not illustrated9#1.$he !ore i!ortant bursae o the 'nee include the ollo&ing(a. Prepatellar bursa bet&een the atella and s'in 8Figure-#2c% d9#'. Inrapatellar bursa bet&een suerior art o tibia and atellarliga!ent 8Figure -#2c@e9#,. uprapatellar bursa bet&een inerior art o e!ur and deesurace o uadrices e!oris !uscle 8Figure -#2c@e9#

Moement-$he 'nee "oint allo&s exion% extension% slight !edial rotation%and lateral rotation o the leg in the exed osition 8see Figures-# and -#5c9#

Aging and JointsO B J E C T I V E


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!uscles% synovial uid% and articular cartilage#CHECKOI!T

25# +hich "oints sho& evidence o degeneration in nearlyall individuals as aging rogresses4

-#2. ArthrolastyO B J E C T I V E

arthr!B"oint> !plastyB lastic reair o9# Although !ost "oints in thebody can be reaired by arthrolasty% the ones !ost co!!onlyrelaced are the his% 'nees% and shoulders# About :..%... hirelace!ents and about 7..%... 'nee relace!ents are eror!ed

annually in the Enited States# During the rocedure% the ends othe da!aged bones are re!oved and !etal% cera!ic% or lastic

co!onents are )xed in lace# $he goals o arthrolasty are torelieve ain and increase range o !otion#

Hi$ Re$a,ement-a%tia /i$ %e$a,ement- involve only the e!ur# Tota /i$ %e$a,ement-involve both the acetabulu! and head o the e!ur8Figure -#2a@c9# $he da!aged ortions o the acetabulu! and thehead o the e!ur are relaced by reabricated rostheses 8arti)cialdevices9# $he acetabulu! is shaed to accet the ne& soc'et% thehead o the e!ur is re!oved% and the center o the e!ur is shaedto )t the e!oral co!onent# $he acetabular co!onent consists oa lastic such as olyethylene% and the e!oral co!onent is co!osedo a !etal such as cobalt/chro!e% titaniu! alloys% or stainless

steel# $hese !aterials are designed to &ithstand a high degree ostress and to revent a resonse by the i!!une syste!# Knce thearoriate acetabular and e!oral co!onents are selected% theyare attached to the healthy ortion o bone &ith acrylic ce!ent%&hich or!s an interloc'ing !echanical bond#

Knee Re$a,ement-Knee %e$a,ement- are actually a resuracing o cartilage and%li'e hi relace!ents% !ay be artial or total# *n a tota nee %e$a,ement%the da!aged cartilage is re!oved ro! the distal endo the e!ur% the roxi!al end o the tibia% and the bac' surace othe atella 8i the bac' surace o the atella is not badly da!aged%it !ay be let intact9 8Figure -#2d@9# $he e!ur is reshaed and

)tted &ith a !etal e!oral co!onent and ce!ented in lace#$he tibia is reshaed and )tted &ith a lastic tibial co!onentthat is ce!ented in lace# * the bac' surace o the atella is badlyda!aged% it is relaced &ith a lastic atellar i!lant#*n a $a%tia nee %e$a,ement7 also called a unicompartmentalknee replacement% only one side o the 'nee "oint is relaced#Knce the da!aged cartilage is re!oved ro! the distal end o thee!ur% the e!ur is reshaed and a !etal e!oral co!onent isce!ented in lace# $hen the da!aged cartilage ro! the roxi!alend o the tibia is re!oved% along &ith the !eniscus# $he tibia isreshaed and )tted &ith a lastic tibial co!onent that is ce!ented

into lace# * the bac' surace o the atella is badly da!aged% itis relaced &ith a lastic atellar co!onent#Researchers are continually see'ing to i!rove the strength o


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the ce!ent and devise &ays to sti!ulate bone gro&th around thei!lanted area# otential co!lications o arthrolasty includeinection% blood clots% loosening or dislocation o the relace!entco!onents% and nerve in"ury# +ith increasing sensitivity o !etal detectors at airorts andother ublic areas% it is ossible that !etal "oint relace!ents !ayactivate !etal detectors#

accessory ligaments

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