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Shoulder anatomy and biomechanics

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By Dr. Raham Bacha
From Lecture Notes
Of
Professor. Dr. S. Amir Gilani.

Published in: Health & Medicine

Shoulder anatomy and biomechanics

  1. 1. قالو سُبحانك ل ا ع لام لنا ال اما عا لمتنا انك انت العليمُ الحكيم Surah Al Baqarahverse 32
  2. 2. By: Dr. Raham Bacha MD, MSc Sonology Gold Medalist (UOL) PhD Ultrasound The university of Lahore
  3. 3. BY
  4. 4. Gleno-humeraljointhasthewidestrangeofmovementcomparedwithanyotherjointinthebody,thisisaccomplishedthroughsacrificeofthebonystabilitywhichisseeninmostjoints.
  5. 5. Thegleno-humeraljointisamulti- axialball-and-socketjoint.Thebonysocketistheglenoid,whichisonlyaboutonethirdoftheareaofthehumeralheadincontrasttotheacetabulumofifhip,whichcoversmostofthefemoralhead.
  6. 6. Tocompensateforthelackofbonystabilitythereisacloselyappliedsystemofligaments,tendonsandmusclesaroundthegleno-humeraljoint,whichactasdynamicstabilisers.ThemostwidelyknownofthesestructuresistheRotatorCuff.
  7. 7. HUMERUS: Thehemisphericalarticularsurfaceisborderedbytheanatomicalneckofthehumerusandiscoveredbyhyalinecartilage.GreatertuberosityLieslateraltotheanatomicalneck.Ithasthreefacets.
  8. 8. 1.Thesuperiorfacetforinsertionofthesupraspinatustendon 2.Themiddlefacetliespostero-inferiorto"1".andisthesiteofinsertionfortheinfraspinatustendon. 3.Theposteriorfacetliesposterio-inferinrto"2."theinsertionoftheteresminortendonoccursonit. Lessertuberosity-liesanteriortothehumeralhead. subscapularistendoninsertsonitsapex. Bicipitalgrove-Liesbetweenthegreaterandlessertuberosities.Isnormallyoccupiedbythelongheadofbicepstendm.
  9. 9. Acromion Broad,flatplateofbonethatiscontinuouswiththespineofthescapula.Liessuperiortothegleno-humeraljoint.Articulateswith theclavicle Projects from the superior aspect of the neckof the scapula and lies anterior to the gieno- hurneraljoint Coracoid Process
  10. 10. TheAcromiumandtheCoracoidProcessarejoinedbythecoracoTacromialligamenttoformacontinuousprotectivearchovertheshoulderjoint.Therotatorcuffandthelongheadofbicepstendonmaybecomecompressedbetweenthehumeralheadandthecoraco-acromialarch-RotatorCuffImpingementSyndrome.
  11. 11. Coveredwithhyalinecartilage.Connectedtothelateralaspectofthescapulabyabroadneck.Theglenoidlabrumisawedge-shapedfibrocartelagenousstructureattachedtothemarginofthebonyglenoid.Thisincreasesthestabilityofthegleno-humeraljointandcushionsthehumeralhead. Glenoid
  12. 12. Attachedtothemarginofthearticularsurfaceoftheglenoid,externaltothelabrumandtothelabrum Humeralattachment:Anatomicalneckofthehumerus, exceptinferiorlywhereitattachesmoreinferiorlytothemedialshaftofthehumerus.Thesynovialmembraneoftheglenotumeraljointlinesthecapsule.Thesuperiormiddleandinferiorgleno-humeralligamentsstrengthenthecapsuleanteriorly.Thecoraco- humeralligamentstrengthensthecapsulesuperiorly. Capsule
  13. 13. Therearetwobreachesinthecapsuleoftheshoulderjoint 1.Abovethesuperiorgleno-hunieralligament,forthetendonofthelongheadofbiceps. 2.Betweenthesuperiorandmiddleglano-humeralligament'sforthecommunicationwiththesubscapularbursa,whichliesbetweenthecapsulaandthesubscapularistendon.Thisbursamayextendsuperiorlytoliebeneaththecoracoidprocesstoformsubcoracoidbursa,however,thisbursausuallydoesnotcommunicatewiththesubscapuiarisbursaortheshoulderjoint. 3.OccasionallythereisasmalldefectInthebackofthecapsuleforasmallinfraspinatusbursa.
  14. 14. Arisesfromthesubscapularfossaandinsertsontheanterioraspectofthelessertuberositybyabroad,thicktendon.Separatedfromthecoracoidprocessbythesubcoracoidbursaandtheshouldercapsulebythesubscapularisbursa.Fibresfromthesubscapularistendonincombinationwithcapsularfibers,crossthebicipitalgrove, formingthetransversehumeralligament. Rotator cuff Subscapularis
  15. 15. Arisesfromthesupraspinousfossaofthescapula.Passesanteriorlyandlaterallybeneaththecoraco-acromialarchtoinsertonthesuperiorfacetofthegreatertuberosityofthehumerusbyabroad,"beakshaped"tendon.Thelongheadofbicepstendonmarkstheanteriormarginofthetendon. Supraspinatus
  16. 16. Arisesfromtheinfraspinousfossaofthescapula.Itstendonblends(mix)withthesupraspinatustendonandinsertsonthemiddlefacetofthegreatertuberosityofthehumerus. TeresMinor Arisesfromtheuppertwothirdsofthelateralborderofthescapulaandinsertsontheinferiorfacetofthegreatertuberositybyathickflattendon. Infraspinatus
  17. 17. Theshortheadarisesfromthecoracoidprocess. thelongheadarisesfromthesupraglenoidtubercleandtheglenoidlabrumbyalong,roundtendon. Theproximaltendonlieswithinthegleno-humeraljointasitpassesantero-laterallytothebicipitalgroovewhereitpassesbeneaththetransversehumeralligamentandthroughtheshouldercapsule. Thetendontakeswithit,throughthecapsule.asheathofsynoviumforavariabledistanceintothebicipitalgrooveThetendoninsertsontheradialtuberosityandthebicipitalaponeurosis. Biceps Brachii
  18. 18. Arisesfromthelateralonethirdoftheclavicle,thelateralborderoftheacromion,thespineofthescapulaandthefasciaoftheinfraspinatusmuscle.itisabroad,flatmusclethatconvergeslaterallytoinsertatthedeltoidtubercleonthelateralshaftofthehumerus. Deltoid
  19. 19. Bursae Thesubacromial-subdeltoidbursaseparatesthedeltoidfromtheunderlyingrotatorcuff,thelongheadofbicepstendonandthegreatertuberosity.Itextendsmediallyundertheacromionanddoesnotcommunicatewiththegleno-humeraljoint.Thesubscapularissubcoracoidandinfraspinatusburshavebeendiscussedearlier.
  20. 20. ThemusclesoftherotatorcuffandthetendonofthelongheadorbicepsplayacrucialroleinthestabilityoftheshoulderjointbyactingasantagoniststomusclegroupsactingintheOppositedirection.Theantagonisticactionoftherotatorcuffmusclesmaintainsthehumeralhead,centeredintheglenoidthroughthefullrangeofshouldermovement.
  21. 21. Inabduction,thedeltoidmuscletendstodrawthehumerussuperiorly.Thesupraspinatusmuscletendoncontractsatthebeginningofabduction, therebyresistingthesuperiormovementofthehumeralhead.Thesupraspinatusmuscleisassistedinthisfunctionbythelongheadofbicepstendon,whichalsoresiststhesuperiormovementofthehumeralhead.
  22. 22. Whenthereisalossofbalancebetweenthesupraspinatusmuscle,thelongheadofbicepstendonandtheactionoftheabductors,therotatorcuffandtheadjacentsofttissuesbecomecompressedbetweenthehumeralheadandthecoracoacromialarch.Thisisthebasisofrotatorcuffimpingementinamajorityofcaseswherenobonycauseisfound.
  23. 23. 1.Abduction 2.Adduction 3.Flexion/Extension 4.Internal rotation 5.External rotation 6.Circurnduction-Which is aconibinatior) of the above movements The planes of movement of the shoulder joint are:
  24. 24. Trueabductionoccursthroughaverticalplane, anteriortothecoronalplane,inlinewiththeaxisofthescapula. •Thedeltoidisthemainabductorofthearm. •Thesupraspinatusisimportantintheearlyphasesofabductionandthenhelpstomaintainthejointstabilitybyrestrainingthismovement. •Theremainderoftherotatorcuffmuscleshelptomaintainthehumeralheadwithintheglenoid. Abduction
  25. 25. Thereverseofabduction Latissimusdorsi,teresmajor, subscapularisandthepectoralmusclescombinetoeffectactiveadduction. Adduction
  26. 26. •ItIsinaplaneat90degreestotheplaneofabduction.Thebisepsbrachii,coraco- brachialis,pectoralismajorandtheanteriorfibresofthedeltoidmusclearethemainflexors. •Theposteriorfibresofthedeltoidandtheteres_majorarethemainextensorsoftheshoulderwiththelatissimusdorsiandthesterno-costalfiberesofthepectoralismajorrestrainigfromfullflexion. Flexion/Extension
  27. 27. Internalrotationiseffectedbysubscapularis,teresmajor,latissimusdorsi, pectoralismajorandtheanteriorfibresofthedeltoid. Externalrotationiseffectedbyinfraspinatus, theposteriorfibresofthedeltoidandtheteresminor. Rotation
  28. 28. Thismovementisacombinationofalltheabovemovements,withthehumerusdescribingacircleoraconecentredontheglenoid. Movementofthescapulaalsofacilitatesthismovement. Circumduction
  29. 29. The structures successfully evaluated by ultrasound include: •The rotator cuff tendons •The long head of biceps tendon •Bursaearound the shoulder •Impingement of the above structures on the coraco-acromial arch •The bony structures of the shoulder •The A-C joint •The muscles around the shoulder
  30. 30. The advantages of ultrasound include The ability to examine the shoulder as it is moved through its normal range of movement Sensitivity and specificities have been reported in the 90% range Easy comparison with the opposite side The ability to palpate and localisesites of pain and tenderness with the ultrasound transducer Wide availability Relatively low cost
  31. 31. The disadvantages of ultrasound include Highly user dependent Clinicians find it difficult to interpret images A number of conditions cannot be evaluated most labralabnormalities most bony lesions capsulitis A plain film examination should always be performed in conjunction with the ultiasound. This will assist in detection of bony lesions and fine calcifications in the rotator cuff
  32. 32. Tears Tendonitis Impingement Tendon Dislocation
  33. 33. Tears Occurmostlyindegenerateorinflamedtendonsandthereforareuncommonintheyoung.Alargeamountofforceisrequiredtotearanormaltendon.About92%ofrotatorcufftearsareofthechronictype,mostcommonlyrelatedtoimpingementandtendonitis. Only 8% of tears are acute and due to a single traumatic episode. 50% of patientswith rotator cuff tears give no History of injury. The tear of supraspinatusis common.
  34. 34. Diagnostic: Absence of the supraspinatus tendon A gap within the tendon filled with fluid or blood. A hypoechoic cleft. Focal thinning of the tendon with loss of the normal convex contour of the subdeltoidfat plane
  35. 35. Inconclusive But Suggestive Signs: An echogenic line in the tendon An inhomogeneous area of echogenicity within the tendon Fluid in the subdeltoidburs? Fluid in the biceps tendon sheath
  36. 36. Tears should be visible in two planes but may be more obvious in one plane than the other. Laminar tears.horizontally in the plane along the tendon. Tearsareusuallymoreobviouswhenthetendonisputunderstress.Thisisusuallyachievedbyplacingthearminadductionandinternalrotationthatisachievedbyplacingthearmbehindtheback.Ifthisisnotpossiblethenthearmshouldbeplacedinextension
  37. 37. TENDONITIS Mean inflammation of a tendon, it is a type of tendinopathy. This usually occurs as a result of aRepetitive micro-trauma due to over use bSubacromialimpingement
  38. 38. SONOGRAPHICFEATURESOFTENDONITIS Decreaseinechogenicity Fluidinthetendonsheathoradjacentbursa Calcification-withacutecalcifictendonitisthecalciumisusuallyliquidandmayruptureintothejointorsubdeltoidbursa.Withchronictendonitis–solidcalcificationmayoccur. Tendonitiswilloftenprogresstotendondegenerationandatear
  39. 39. Tendonitiswilloftenprogresstotendondegenerationandatear. Bicepsteildonitisisrelativelycommonandisusuallyassociatedwithfluidinthebicepstendonsheath. Fluidbyitselfisnon-specificandmaybeduetoashoulderjointeffusionorrotatorcuffpathology.Asmallamountoffluidinthebicepstendonsheathisnorrnal.
  40. 40. Itreferstocompressionoftherotatorcuffandthelotuheadofbicepstendonbetweenthehumeralheadandthecoraco-acromialarch. 90%ofcasesareduetoshoulderinstability 10%areduetomechanicalcausessuchasosteophytesontheacromionorA-Cjoint. Thisisthemostcommoncauseofchronictendonitisandrupture.
  41. 41. Rotatorcuffimpingementmaybedividedintothreestages Stage1:swellingandhemorrhagewithinthesupraspinatustendon Stage2:Thetendonbecomethinandfibrotic Stage3:Thetendontears
  42. 42. sonograpicSigns DirectSigns: Bunchingofthesupraspiriatustendonagainsttheacromiononabduction Fluidmaybemilkedlaterallyinthesubdeltoidbursawithabduction Thehumeralheadmaybeforcedinferiorlyatthetopofabduction
  43. 43. Indirect Signs: The rotator cuff does not pass freely beneath the acromion(it is sometimes difficult to separate guarding of a painful shoulder from impingement in this situation) Biceps or supraspinatus tendonitis with no apparent cause. Thickening of the subdeltoidbursa with no apparent causa
  44. 44. Thelongheadofthebicepstendonisheldinthebicipitalgroovebythetransversehumeralligament.Ruptureofthisligamentallowsdislocationofthebicepstendon.Itusuallydislocatesmedially,eitheranteriororposteriortothesubscapularistendon. Thisiscommonlyassociatedwithtendonitisandtearsofthetendonduetomechanicalabrasionofthetendononthelessertuberosity.
  45. 45. •Anemptybicepitalgroove(Bewareofincorrecttransducerangle) •Thetendonisvisualizedinadislocatedposition. •Thetendonmaybeseentodislocatewithexternalrotationorwithflexion/extension. •Underlyingcorticalirregularity SonographicSigns:
  46. 46. •Subaciornial-subdeltoidbursa •Fluid in this bursa is highly suggestive of a rotator cuff tear. •It may also be seen in impingement or in inflammatory arthritidessuch as rheumatoid arthritis, which is often associated with synovial thickening. •Always check laterally down to the deltoid tubercalas this bursa is quite extensive.
  47. 47. This may communicate with the shoulder joint. In these cases fluid will be seen at this site with a joint effusion Sub-coracoid bursa This bursa may also communicate with the shoulder joint Isolated fluid may be seen in the subcoracoidbursa with subscapularisimpangment. Infraspinatus bursa
  48. 48. Ultrasoundissensitivefordetectionoffracturesinthevisiblebonysurfaces, especiallythegreatertuberosity. Undisplacedfractures of the greater tuberosity are commonly missed on plain films. FRACTURES
  49. 49. The capsule of the A-C joint normally has a convex superior surface Abnormal findings include: Widening of the joint Fracture fragments Degenerative change Ganglion cysts A-C JOINT
  50. 50. Comparison views of the right and left AC joints in this patient reveal separation of the AC joint on the right side as demonstrated by the increased distance between the acromion and the clavicle (curved arrow). AC Joint Separation
  51. 51. Hematomas,tearsandtumorsinthemusclesandsofttissuessurroundingtheshoulderjointareusuallybevisible. Detectionoftheseabnormalitiesisassistedbytheabilitytoexaminetheexactsateofswellingortenderness PERI-ARTICULAR ABNORMALITIES
  52. 52. Manydifferenttechniquesforevaluatingtheshoulderbyultrasoundhavebeendescribed.Theidealseemstobeexaminationofeachcomponentoftherotatorcuffmorphologicallyandfunctionally.
  53. 53. •Ahighfrequency,lineararray,smallpartstransducerwithgoodnearfieldisESSENTIAL. •Adjustoutput(power)toavoidoversaturation—rememberallstructuresaresuperficial. •Selectappropriate2Dgreyscalemap, persistence,framerateandlinedensitytooptimisetheimage. •Hardcopyimagesaretakenaccordingtodepartmentprotocol,withadditionalviewsofrelevantpathology. •UsefultorecorddynamicassessmentonVCR. EQUIPMENT:
  54. 54. TECHNIQUE: BOTH SIDES ARE EXAMINED, THE NORMAL FIRST this "sets up the equipment, the patient, and yourself. A formal routine is followed to ensure that no abnormality is overlooked. Each phase leads onto the next, making it easier for the novice to maintain their anatomical bearings.
  55. 55. The routine is, in order BICEPS Transverse,longitudinalanddynamic(internalandexternalrotation).SUBSCAPULARIS Longitudinalanddynamic(internalandexternalrotation). CORACO-ACROMIALLIGAMENT Longitudinalanddynamic(internalandexternalrotation) SUPRASPINATUS Transverse,longitudinalanddynamic(passiveandactiveabduction)
  56. 56. INFRASPINATUS -Longitudinal and dynamic (internal and external rotation). TERES MINOR - Longitudinal and dynamic (internal and external rotation). ACROMIO -CLAVICULAR JOINT Longitudinal and dynamic (abduction, adduction and forward flexion). AREA OF PATIENT'S CONCERN ASK the patient what movements are difficult or painful, and if they have any "sore spots". Throughout the examination, if an area of concern is encountered, reference is made back to the normal side.
  57. 57. Bonylandmarksareparticularlyusefulinlocatingthevarioustendons.Whenstructuresofuncertainoriginareencounteredtherule"whenindoubt,moveit"isveryuseful,providedthesonographerhasasoundknowledgeofanatomy.
  58. 58. Itistransverseviewatthelevelofthelongheadofthebicepstendonatitsintra- capsularlevel.Notetheechogenictendonseparatingthesupraspinatus(laterally)andsubscapularis(medially)tendons.Thisregioniscalledtherotatorcuffintervalanditisimportantnottoconfusethisechogenicfocus,oftenflankedbytwohypoechoicareas,witharotatorcuffabnormality. The Rotator Cuff Interval
  59. 59. The patient sits facing the monitor, preferably on an adjustable chair, with their arm by their side, hand resting on the outer thigh. In this position the bicipitalgroove lies anteriorly —(if the hand lies in the lap, the groove is quite medial, and can be difficult to located. Placing the transducer horizontally on the anterior upper shoulder, the bicipitalgroove can be seen —this is a VERY IMPORTANT bony landmark. BICEPS:
  60. 60. TRANSVERSE—slidethetransducerfromsuperiortoinferiorintheaxial(horizontal)position,fromtheacromiontothebellyofthebicepsmuscle,keepingthetransducerperpendiculartothetendon."Heelandtoe" movementswiththetransducermaybenecessarytoshowtendontextureand/orfluidinthegroove.Thebicepstendonisusuallyovalandoftenlieseccentricallywithinthegroove.Thetransversehumeralligamentcanbeseensuperficialtothetendonasathinechogeniclineandisacontinuationofthefasciaoverlyingthesubscapularistendon.
  61. 61. Biceps Tendon -Transverse View
  62. 62. Longitudinal-Rotatingthetransducerthrough90degrees,thetendonisanechogenicfibrillarstructurelyinganteriortothestronglyechogenichumeralshaft.Again,"hee/andtoe" movementswillcompensateforanisotropy.Examinetendonfromacromiontomusclebelly.
  63. 63. Biceps Tendon Long axis Demonstrate the biceps tendon in a sagittal view (white arrow) Note the Classic fibrillar echo pattern evident within the tendon also note the transverse humeral ligament in this plane (small white arrow) Dynamic —The oiclpitaigrocyi-e is scanned transversely as the arm is Inter-sally anaexternally rotated. any subluxation of the tendon should be visible on the screen —t is usually obvious to the patient as a palpable and often audible cli ,kScannincthe tendon longitudinally with it under tension (patient to pull up the -forearm agaulstyour pushing)also show movement of the tendon fibres
  64. 64. Lonoitudinai—From tnetransverse vie■A" of the e biceps. the insertion of tne subsoapulanstendon can be seen on the medial aspect of the lesser tuberosity The insertion is the apex of a somewhat triangular tendon. so care should be taken to observe the whole insertion —it can be 3 to 6 ems wide. With the arm in external rotation. the whole length of the tendon can be seen under the subdeltoidbursa SUBSCAPULARIS
  65. 65. -Short Axis Figure illustrates a normal subscapularistendon (arrows) in a short axis, or transverse plane. Note the deltoid muscle labeled 0) superficially, as well as the humeral head (labeled H) and lesser tuberosity (labeled LT). Remember, the transducer must be oriented almost longitudinally in order to visualize this tendon in a transverse plane SubscapittarisTendon
  66. 66. SubscapularisTendon -Long Axis
  67. 67. Dynamic—Internalandexternalrotationofthearmwilldemonstratethepassageofthetendonandverybroadmusclebellyunderthecoracoidprocess. Bursalfluidmaybecomemoreevident, andimpingementofthebursaormuscleonthecoracoidcanbeseen.
  68. 68. Attheendoftheexaminationofthesubscapularis,thetransducershouldbehorizontalwiththecoracoidprocessandsubscapularistendonvisible.Fixthemedialendofthetransducerandrotatethelateralendsuperiorly,sothatalinedrawnthroughthetransducerwouldpassthroughthenippleontheothersideofthebody.Thecoraco-acromnialligamentisvisibleasapairofechogenicthinlineswithaninterveningthinsonolucentline,runningbetweenthecoracoidandtheacromion.Atthecoracoidtheligamentappearstopasssuperficiallybutattheacromiontheligamentpassesdeeptothebone,andisoftennotwellseen.Ifthepatienthashadprevioussurgeryoftheshoulderthelateralpartofthe ligamentmaywellhavebeenremoved. CORACO -ACROMIAL LIGAMEN
  69. 69. Dynamic-OninternalandexternaliotationtIieiotatorcuffisseenglidingbeneaththeligamentandthedeltoidmusclemovesslightlyfromsidetosidesuperficialtoit-theligamentshouldbeassessedforflexibility, fluidinthesubdeltoidbursaquiteoftenbeingseenbeneathit.
  70. 70. Transverse-thesupraspinatustendoninsertsontothegreatertuberosityandformsthesuperiorandlateralportionsofthecuff:normallyitiscoveredbythebonyacromion,sohastobeputLindertensiontoobserveitinitsentirety,thisinvolvesmovingthearmintovariouspositions.Theeasiestpositionistoflextheelbow,placethepalmofthehandontothehip,andtucktheelbowintothesideorextendthearmdownbythesideandturnthethumbinward:orplacethearmbehindtheback,makingsurethereisno"gap"betweentheelbowandthetorsothiscanbequitedifficultforelderlypatients.Acombinationof.thesethreemanoeuvrescanbeattempted. SUPRASPINATUS
  71. 71. Thetransducerisplacedontheacromioninthecoronalplane,andslidlaterallytheacousticshadowoftheacromionisreplacedbyapairofparallelcurvedechogeniclinesTheanteriorlineisthesubdeltoidbursaandtheposterior,thehumeralhead. Articularcartilageisseenasathinhypoechoiclineanteriortothehumeralhead.Movethetransducerinthisplaneanteriorlyuntilthebicepstendonisseenasanovalechogenicstructure-THISISAVERYIMPORTANTLANDMARK-asthesupraspinatustendonimmediately
  72. 72. posteriortoitisknownasthecriticalzoneofthetendon, ie.,itismorepronetodegenerativechangebecauseofpoorvascularity.Movingthetransducerposteriorlywilldelineatethejunctionofthesupraspinatusandinfraspinatus,seenasanobliqueechogenicline,neartheposterioredgeoftheacromion.Scanthetendondownontoitsinsertionontothehumeralhead,notinganypittingorbonychangesonthehumeralhead.possiblyindicativeoftears.Continuescanninginthesameplaneontothehumeralhead,toruleoutfluidinthesubdeltoidbursabeyondthetendoninsertion-•careshouldbetakentoscanverylightly,asfluidcanbeveryeasilydispersed.
  73. 73. Lorigi_tudinal-Rotate the transducer through 90 degrees, and use the acromion as a landmark. The anterior part of the supraspinatus lies anterior to the acromion. The tendon has a sickle shape Often the coraco-acromial ligament is seen in cross-section immediately superficial to the tendon The ligament is iistrallyan echogenic dot. often with a sonolucentcentre. Sliding the transducer slightly anterior to the supraspinatus the tendon of long head of biceps is again encountered. The mid portion of the tendon has an "eagles beak" appearance. 1 he acoustic shadow of the acromion resembles the head of the eagle, the smooth convex upper border of the tendon is the top of the beak, and the top of the humeral head is the bottom of the beak The hook of the beak is the greater tuberosity.
  74. 74. Slidingthetransducerslightlynioreposteriorly,thehookofthegreatertuberosityislostandthebeakhasaflatterappearance,resemblingmorea"crow'sbeak".
  75. 75. Supraspinatus Tendon -Long Axis
  76. 76. Supraspinatus Tendon -Short Axis
  77. 77. Dynamic---Withthetransducerparalleltothelongitudinalplaneofthesupraspinatustendon, abductthepatient'sarmwhilstwatchingthetendonmovementonthescreen.Thetendonandsubdeltoidbursashouldslidecompletelyundertheacromionorcoraco-acrornialligament.Themovementshouldbeperformedbythepatient(active)andbythesonographer(passive)withthearmindifferentdegreesofinternalandexternalrotation.
  78. 78. Thedynamicprocedureshouldbeperformedsothattheanteriorandmid(andoccasionallyposterior)portionsofthetendonareexaminedaspathologycanoccurinanyregionwithanymovement,dependingontheclinicalsituationeginsomeoccupations,wheremanymovementsareperformedwiththearmsoverthehead,theposteriortendonsuffersmorethantheanterior,andviceversa.Itshouldbenotedthatwhenthc,armisinmarkedinternalrotation,thereisanaturallimittotheamountofabductionthatcanoccur(approximately90degrees)
  79. 79. Longitudinal—Withthepatient'sarmininternalrotation,placethetransduceronthespineofthescapula,alignedtoitslongitudinalaxis.Slideinferiorlyandlaterallytodemonstratetheinfraspinatustendoninsertionontothegreatertuberosity. Thenmovebackmediallytothemusculotendinousjunction. INFRASPINATUS
  80. 80. Infraspinatus Tendon -Short Axis
  81. 81. InfraspinatusTendon Tendon-Long Axis
  82. 82. Dynamic —Moving the arm through external and internal rotation demonstrates the tendon moving over the humeral head. Deeper to the tendon the posterior
  83. 83. glenoid labrum can be seen as a thin echogenic triangular structure "leaning“ on the humeral head. Effusions in the gleno-humeral joint are easily identified in this position as sonolucentcollections adjacent to the glenoid labrum. These collections change shape with the movement of the humerus.
  84. 84. Longitudinal-Fromtheinfraspinatusposition,slidethetransducerinferiorly,approximately1cm.ThethickerTerestendonresemblesaship'sprow.becomingmoreelongatedasthearmisinternallyrotated.Thetendonitselfismoreobliquethaninfraspinatus—toviewlongitudinally,rotatethemedialend/,ofthetransducerslightlyinferiorly. TERES MINOR
  85. 85. Dynamic--Again,oninternalandexternalrotation,thetendonassessed,ascanbeanyfluidcollectionsintheposteriorjointspace.
  86. 86. hisisusuallyeasilypalpable.Ifnot,inthelongitudinalsupraspinatusposition,slidethetransducerslightlyantero--mediallyacrosstheacromionandthejointshouldbecomeobviousasasonolucentinvertedtrianglebetweentheacousticshadowsoftheacromionandtheclavicle("Thefatseagullsign").Scanfromanteriortoposterior. ACROMIO-CLAVICULAR JOINT
  87. 87. Dynamic—Frorntlierestingposition(armextendeddownbythepatient'sside), abductandadductthearm,observinganychangeintheshapeofthejointcapsule. Alsoobserveanymovementsofthebonesthemselves--especiallyintheforwardflexionposition.
  88. 88. •ThisistheBASICexamination:otherareasofconcerninclude- •thesuprascapularnotchandspino-glenoidnotch(affectingthe •suprascapularnerve), •theshortheadofbiceps, •muscletextureindisusesyndromes(especiallyinfra-andsupraspinatus) •rhomboids, •deltoidoriginandinsertion •pectoralismuscles •triceps

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