welcome everybody to my presentation on shoulder joint
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DESCRIPTIONWelcome Everybody To My Presentation On Shoulder joint. Introduction. It is a ball and socket type of synovial joint It is a multiaxial spheroidal jt Roughly hemispheric head of the humerus form the ball and shallow glenoid fossa of scapula form the socket. - PowerPoint PPT Presentation
IntroductionIt is a ball and socket type of synovial jointIt is a multiaxial spheroidal jtRoughly hemispheric head of the humerus form the ball and shallow glenoid fossa of scapula form the socket.Skeletally jt is weak. It depends for stability and support on its surrounding muscle rather than its shape and ligaments.Only one third of humeral head is in contact with the glenoid fossa at any time.
Angle of inclination: in the frontal plane, the axis of the head and neck of humerus form an angle of 130-140 with the long axis of shaft of femur.Because of this angulation, the centre of the humeral head lies about 1cm medial to the long axis.
Angle of retroversion: an angle to the shaft of the humerus, the axis of the head and neck is rotated backwords against the shaft some 30-40, this is caled the angle of retroversion.
Articular surfaceTwo articular surface:
glenoid fossa is situated at the supero-lateral angle of the scapula faces laterally, anteriorly and slightly superiorly. Concavity of glenoid fossa is irregular and less deep than convexity of head of the humerus. The articular surface the fossa is little more than the head of the humerusIt ls covered by hyaline cartilageHyaline cartilage is thinner centrally and thickest peripharally
Head of the humerus:
It represents two-fifths of a sphereIt faces superiorly, medially and anteriorlyCovered by hyaline cartilage On the humerus hyaline cartilage is thickest centrally and thinner peripherally
Joint capsuleIt is like a cylindrical sleeve and situated between two bones Majority fibres of the capsule passes horizontally between scapula and humerus. But some oblique and transversre fibres are also found On the scapula, the capsule attaches just outside the glenoid labrum anteriorly and inferiorlyOn the humerus, capsile attaches to the anatomical neck,medial to the greater and lesser tubercle
Continuation Anterior part of the capsule is thickened and strengthened by three glenohumeral ligaments. Superoposterior part is strengthened by coracohumeral ligamentIn anatomical position of the arm the lower part of the capsule is lax and forms a redundant fold.In abduction of arm lower part become s taut
Continuation It is supported by the:supraspinatus (above)Infraspinatus and teres major (behind)Subscapularis (in front)Long head of triceps (below)
Capsule has two or three openings:Below the coracoid processBetween two tuberclesInbursa undea the infraspinatous tendon
Synovial membraneThis lines the capsule and covers parts of the anatomical neck The synovial membrane is reflected from the margin of the glenoid cavity over the labrum The tendon of the long head of the Biceps brachii passes through the capsule and is enclosed in a tubular sheath of synovial membrane
Glenonoid labrumIt is lintra-articular structureIt is a fibro-cartiliginous rim round the glenoid fossaIt is triangular in section4mm deepIts base attaches to the margin of the glenoid fossa. Outer surface attaches to the joint capsule superiorly and posteriorlyInner surface is in the contact of head of humerusIt protects the joint and assists lubrication
Capsular Ligaments Glenohumeral ligament:Superior glenohumeral ligament:It is splender shapedIt arises from upper part of the glenoid labrumIt runs laterally parallel to the biceps tendon to the upper tendon to the upper surface of the lesser tubercle
Middle glenohumeral ligament:Arises from below the superior glenohumeral ligamentAttaches to the humerus on the front of the lesser tubercle below the insertion of subscapularis
Inferior glenohumeral ligamrent:
It is best developed of the three ligamentsIt arises from the anterior border of the glenoid labrumIt descends slightly obliquely to the anteroinferior part of the anatomical neckThe antero-superior edge of the inferior ligament is thickened and known as superior bandThe thickening of the anterior part of the capsule to which inferior ligament attaches is known as axillary pouch
Function of glenohumeral ligament:They have no stabilizing functionLateral rotation of the humerus put all three ligaments under tensionMedial rotation relaxes themIn abduction only the middle and inferior ligament become taut and superior ligament become relaxed
Transverse humeral ligament:It is formed by some of the transeverse fibres of the capsule At the upper end of the intertubercular groove, the transverse humeral ligamentbridges the gap between the greater and lesser tubercles.It hold the biceps tendon in the intertubercular groove.
Intra- articular ligament These ligaments are considered as accessory ligamentCoracohumeral ligament:It is strong and broadIt arises from the lateral border of the coracoid process near its root.It passes laterally above the intertubercular groove to attach to the anatomical neck to the greater and lesser tubercleAnterior part of the ligament is free. But laterally it fuses with the tondon of subscapularisIt inserted in lesser tubercle
Coracoacromial ligament:It is not directly associated with the jointIt is a strong and triangular ligamentIt forms with the coracoid and acromion process, a fibro- osseous arch above the head of the humerusIts anterior and posterior part is thicker than intermediate part.
Bursae between the subscapular tendon and articular capsuleSometimes between the infraspinatous tendon and capsuleSubacromial bursa: between deltoid and capsule.On the superior acromial aspectBetween coracoid process and capsuleSometimes behind coracobrachialisBetween teres major and the long head of biceps
Muscle Deltoid (anterior fibre):Origin: Arises from the anterior border and upper surface of the lateral third of the clavicleInsertion:Function:
Deltoid (middle fibres):Origin: Arises from the lateral margin and upper surface of the acromion.Insertion:Function:
Deltoid (posterior fibre):Origin: Arises from the lower lip of the posterior border of the spine of scapula, as far back as the triangular surface at its medial end.Insertion:Function:
Supraspinatous:Origin: Medial two-thirds of the supraspinatus fossa of scapulaInsertion: Superiorly of the greater tubercle of the humerus Function:
Serratus anterior:Origin: Originates on the surface of the upper eight ribs at the side of the chest and inserts along the entire anterior length of themedial border of the scapulaInsertion:Function:
Trapezius:Origin: Arises from theoccipital bone, the ligamentum nuchae, the spinous process of the seventh cervical, and the spinous processes of all the thoracic vertebraeInsertion: It inserts on the lateral clavicle, the acromion process, and into the spine of the scapula.Function:
Infraspinatous:Origin: infraspinatus fossa just below the spine of the scapula Insertion: Posteriorly on the greater tubercle of the humerus Function:
Teres minor:Origin: Posteriorly on the upper and middle aspect of the lateral border of the scapulaInsertion: Posteriorly on the greater tubercle of the humerus Function:
Blood and nerve supply Artial supply: it is from numerous sources around the jointSuprascapular branch of subclavian artery Acromial branch of thoracoacromial arteryAnterior and posterior circumflex humeral arteriesThree are all branches of axillary artery
Venous drainage is by similarly named veins which drains into the external jugular and axillary veinsLymphetic drainage of the joint is to the lymph nodes within the axilla and passes into subclavian lymph trunkNerve supply:SuprascapularAxillary]SubscapularLateral pectoralMusculocutaneousRoot value of C5,6 and7
Stability Factors responsible for stability:The glenoid labrum- it deepening the glenoid fossa. And make the joint surface congurentRotator cuff- Most important factorVery close it the joint and fuse with lateral part of capsule.They act as ligamentsInferior part of capsule is weak and unsupported. But as the arm gradually abducted the long head of triceps and teres major support this
Muscle of pectoral girdle and humerus:Long head of biceps: gives support over the superior part of jointLong head of triceps: gives support below the joint Coracoacromial arch: it prevent upward displacement of the head of the humerus
Movement Flexion : Flexion and extension occur about an axis prependicular to the plane of the glenoid fossaIn flexion the arm moves forward and medially at an angle of 45 to the sagital plane.Range is 110-180It is produced by the anterior fibres of deltoid, pectoralis major, coracobrachialis and biceps
Extension: In extension arm moves backwords and laterallyRange is 70-90Extension is limited by greater tubercle of the humerus coming into contact with the coracoacromial archExtension is produced by the posterior fibres of deltiod, teres major and latissimus dorsi
Abduction:In abduction the arm moves anterolaterally away from the trunkTotal range is 120Only first 30 movement occurs without scapular rotationThe terminal part of the shoulder joint abduction is accompanied by lateral rotation of the humerusIt is due to provide further articular surface on the head of the humerus for the glenoid fossaAbduction of the medially rotated humerus is limited by tension in the posterior capsu