ANATOMY OF SHOULDER JOINTPRESENTOR :DR.B.VAMSHIKIRAN
INTRODUCTION• Shoulder girdle is formed by scapula and clavicle and humerus upper end.• The only skeletal connection of upper limb to trunk is clavicle[scapula is connected only through muscular attachments].• Shoulder area include- -gleno humeral -acromio clavicular -scapulo thoracic -sterno clavicular
• Surface anatomy land marks• Joint structures.• Ligaments and tendons.• Relations ,muscles and nerves.• Blood supply.• Bursae around shoulder joint• Range of movements.• Applied anatomy.
SURFACE ANATOMY• Anteriorly -Clavicle -Tip of coracoid process of scapula -Greater tubercle of humerus. -Deltoid contour -axilla and its folds -medial epicondyle shows head of humerus direction -lateral epicondyle show greater tuberosity direction• Posteriorly –Scapula-acromian,crest of spine[T3] medial and lateral borders,inferior angle
BONES• Clavicle-Lateral end• Scapula• Upper end of humerus• Superior shoulder suspensory complex-itis a group of bony and ligamentous attachments includes coracoid,acromian,glenoid,distal clavicle,coracoclavicular ligament[main bond b/w scapula and clavicle].• Superior strut by middle 1/3rd clavicle a• Inferior strut by lateral scapular body and spine
OSSIFICATION CENTRES• PROXIMAL HUMERUS-3 ossification centre.• Humeral head-ossifies at 6mths• Greater tuberosity-ossifies at 1 to 3yrs• Lesser tuberosity-ossifies at 4 to 5yrs.• Tuberosities coalesce at 6to 7yrs and then fuses to humeral head 7 to13yrs.• Physis close at 14-17yrs girls and 16-18yrs boys.• Proximal physis is extra-articular except at medial aspect
OSSIFICATION CENTRES• CLAVICLE-It’s the 1st bone to ossify .• It has no medullary cavity.• It occurs by intramembranous ossification.• Secondary ossification centres via endochondral.• Medial epiphysis ossifies at 12-19yrs and fuses at 22 to 25yrs.• Lateral epiphysis ossifies and fuses at 19yrs.• It is most commonly #long bone in body.
OSSIFICATION CENTRES• SCAPULA-body,spine,coracoid,acromian,glenoid -Body and spine[posterior] ossify at birth -Coracoid process[anterior]-atavastic epiphysis. - centre at1yr,base at 10yrs,tip at variable - all 3 fuse by 15-16yrs. -Acromian[lateral projection]-fuses by 22yrs via 2- 5centres form at puberty -Glenoid-upper1/4th ossify at 10yrs -lower3/4th appear at puberty ,fuse by22
ACROMIOCLAVICULAR JOINT• Its a plane synovial joint formed by articular facets of lateral end of clavicle and medial acromial margin• Cavity of joint is subdivided ay ARTICULAR DISC which may be perforated• Blood supply- suprascapular thoracoacromial [br. of axillary artery]
SHOULDER JOINT• It’s multiaxial synovial ball and socket[dish]joint.• In anatomical position - -Glenoid articular surface has 7*posterior version -Proximal end of humerus is 45*tilted upwards vertical angle with long axis of humerus and 20* RETROVERTED with reference to transverse distal intercondylar line. -Scapula is 30*anterior to body’s transverse plane• The humeral retroversion is 27* right and 21*left• Anatomical neck and surgical neck
• Glenoid cavity diameters- -transversely-24+/-3mm -superioinferiorly-35+/-4mm -radius curvature 36+/-7mm-articular surface is PEAR shaped due to anterior incisura acetabuli and relatively small and flat. -only 1/4th of humeral head is in contact with glenoid cavity hence greater mobility is seen.
JOINT STABILITYPassive mechanisms like Active mechanisms like• Joint confirmity • Musculo-tendinious• Vacum effect of rotator cuff[dynamic limited joint volume stabiliser]• glenoid labrum • Muscles attaching limb [static stabiliser] to thorax like pectoralis• joint capsule major • Long head of BICEPS• glenohumeral and TRICEPS ligaments• coracoacromial arch[osseo- ligamentous arch]• Scapular inclination
GLENOID LABRUM• It’s a fibrocartilagenous rim attached to margin of glenoid cavity and inc concavity by 50% and suface area of humeral attachment by 75%.• It further strengthens by long head of biceps origin and sup glenohumeral ligament• It is a STATIC stabiliser of joint and prevents excessive rollback of humerus
JOINT CAPSULE• It is lax and attaches along epiphyseal lines of glenoid and humeral head and extends onto surgical neck medially.• Capsule is surrounded by synovial membrane which prolongs along tendon of biceps as tubular sheath• Inf part weakest-resulting in dislocations• APPLIED ANATOMY-OSTEOMYELITIS of humerus upper end spreads directly to joint due to capsule extension to medial side of neck
RELATIONS OF ARTICULAR CAPSULE• MEDIALLY-beyond supraglenoid tubercle andlabrum• LATERALLY-attaches to anatomical neck of humerus• INFERIORLY-attachment extends to surgical neck• SUPERIORLY-deficient for biceps long head passage• ANTERIORLY-reinforced by GLENOHUMERAL LIGAMENTS[sup,middle,inf]
GLENOHUMERAL LIGAMENTS• SUPERIOR-It is the most superior capsular thickening from labrum anterior to long head of biceps at level of coracoid base• It passes under supraspinatus and inserts on ANATOMICAL NECK medial to anterosuperior base of lesser tuberosity.
• MIDDLE GLENOHUMERAL-most variable in size• Arises just inferior to superior GHL and inserts along middle area of ANATOMICAL NECK opposite to lesser tuberosity
• INFERIOR GLENOHUMERAL-It’s the THICKEST part• It is very broad arising from lower half of labrum[anterior,inferior,posterior]• Thick superior margin is called SUPERIOR BAND, rest of it is called AXILLARY POUCH.• Superior band and anterior pouch insert on ANATOMICAL NECK while the posterior pouch on SURGICAL NECK
APPLIED ASPECTS OF GLENOHUMERAL LIGAMENTS• They restrain the selective arcs of abduction and external rotation.• In arm dependent position all are slack.• The SUPERIOR GHL is primary resistrant to inferior translation of adducted shoulder• The MIDDLE GHL limits external rotation at 45* of abduction• The INFERIOR GHL limits external rotation at 45 to 90* of abduction[mainly superior band of it].
• CORACOHUMERAL LIGAMENT-arises from lateral base of coracoid process and extends onto both tuberosities.• It forms roof of bicipitaltendon sheath andstrengtens capsule anteriorlyImportance-resists inferior and posterior translation.• TRANSVERSE HUMERAL LIGAMENT-bridges upper part of bicipital groove through which long head of biceps passes down.
CORACOACROMIAL LIGAMENT• It’s a trapezoidal ligament from base of acromian to apophysis of coracoid• It along with coracoid and acromian forms CORACOACROMIAL ARCH which is a SECONDARY SOCKET to humerus head.• It plays role in resisting upward displacement of humerus
CORACOCLAVICULAR LIGAMENT• Very strong ligament from outer and inferior clavicular surface to coracoid base• 2components-CONOID and TRAPEZOID• IMP FUNCTION-It is prime suspensory ligament of upper extremity that couples”glenohumeral abduction and flexion”to”scapular rotation on thorax”.• Conoid portion is primary restraint to anterior and superior rotation and anterior and superior displacement of clavicle• Trapezoid has relatively less role than conoid part
BURSAE RELATED TO SHOULDER JOINT• SUBACROMIAL BURSA-protect suprspinatus• SUBSCAPULARIS BURSA• INFRASPINATUS BURSA
RELATIONS OF SHOULDER JOINT• SUPERIORLY- coracoacromial arch, subacromial bursa, supraspinatus,deltoid• INFERIORLY- long head of triceps• ANTERIORLY-subscapularis,coracobrachialis biceps short head,deltoid[ant fibres]• POSTERIORLY-infraspinatus,teres minor,deltoid• WITHIN JOINT-Long head of biceps
BLOOD SUPPLY• Anterior circumflex humeral artery[axillaryartery]• Posterior circumflex humeral artry[axillaryartery]• Suprascapular[thyrocervical br.] and subscapular artery[largest br. of axillary artery]
NERVE SUPPLY• Axillary nerve-passes close to surgical neck of humerus abt 5cm below acromian• Musculocutaneous nerve• Suprascapular nerve-Just passes over clavicle
PRINCIPAL MUSCLES AROUND SHOULDER• Primary role -a.movements of arm b.dynamic stabilisation of glenohumeral joint.• There are 14 muscles which are divided into 4 functional groups.they are1.Three heads DELTOID[anterior,middle,posterior]2.Four rotator cuff muscles and BICEPS muscle3.Two axiohumeral muscles[PECTORALIS MAJOR and LATTISMUS DORSI] and TERES MAJOR.4.Scapular muscle group –SERRATUS ANTERIOR,TRAPEZIUS,RHOMBOID MAJOR and MINOR and LEVATOR SCAPULAE
Coracobrachialis ,short head of biceps Long head of tricepsDeltoid- Pectoralis major
• SCAPULA POSTERIOR ANTERIOR supraspinatus subscapularis infraspinatus Teres minor
MUSCLE ORIGIN INSERTION NERVE SUPPL ACTIONDELTOID-4septa origin Deltoid Axillary Acromial fibres-abductorsAnt border lat 1/3rd clavicle tuberosity on nerve[c5,6] From90*Acromian lateral border humerus Anterior fibres-flexors andLower lip crest of spine of medial rotatorsscapula Posterior fibres-extensors and lateral rotatorsSUPRASPINATUS-medial2/3 Greater Suprascapular Initiator ofOf supraspinatus fossa tubercle nerve[c5,6] abduction0*15* upperimpresi steadies humeralheadINFRASPINATUS-medial2/3 Greater Suprascapular Lateral rotator of armof infraspinatus fossa tubercle nerve[c5,6]TERES MINOR-Upper2/3 of Greater Axillary Lateral rotator of armdorsal surface of scapula tubercle nerve[c5,6]SUBSCAPULARIS-medial 2/3 Lesser Upper ,lower Medial rotator andof subscapular fossa tubercle subscapular N adductor of armBICEPS- Radial Musculocutan Strong supinator whenShort head-tip of coracoid tuberosity of eous forearm flexedLong head-supraglenoid posteriorly nerve[c5,6] Flexor of elbow Short head-arm flexor Long head-prevents upward displacement
MUSCLE ORIGIN INSERTION NERVE SUPPLY ACTION PECTORALIS MAJOR Bilaminar tendon on Medial and Adduction and medial Ant surface of clavicl lateral lip.two lamina lateral pectoral rotation of shoulder Ant manubrium[ant are continous nerve Clavicular-arm flexor lamina] Fibres from sternum Sternoclavicular part-• Table of page 143 chaurasia 2nd-6th coastal cartilage and aponeurosis are extension of flexed External oblique twisted and inserted arm against resistance abdominus aponeurosis[post lamin] LATTISMUS DORSI- Winds round lower Thoracodorsal Adduction,extension, Outer lip of iliac crest border of teres major nerve[c6,7,8] medial rotation of post 1/3rd and forms posterior shoulder Posterior layer of axillary fold Helps in voilent lumbar fascia Tendon is twisted expiratory effort T7-12 spinous process upside down insert Climbing muscle Lower 4ribs into intertubercular Holds inferior angle of Inf angle scapula sulcus of humerus scapula in place TERES MAJOR- Medial lip of bicipital Lower Medial rotator and Lower 1/3rd of dorsal groove subscapular adductor arm surface of lateral and nerve[c5,6] inferior angle scapula
scapulaDorsal aspect of scapula Serratus anterior insertion
MUSCLE ORIGIN INSERTION NERVE SUPPLY ACTIONSERRATUS ANTERIOR- Coastal surface of Nerve to serratus Pulls scapula forward8digitations of upper scapula medial border anterior c5,6,7 around chest wall to8ribs 1st digitation sup angle to protract limb root of spine Inf fibres-pull it forward Next two-medial border and rotate Lower 5-inferior angle Steadies scapula Forced inspirationTRAPEZIUS- Upper fibres-posterior Spinal part of Upper fibres[+LS]-Medial 1/3 of superior border of clavicle lat 1/3 accesory nerve- elevate scapulanuchal line Middle fibres-medial motor Middle fibres[+R]-External occipital margin acromian and C3,4-proprioceptive retract scapulaprotuberance upper lip crest of spine Lower fibres[+SA]-Ligamentum nuchae of scapula rotate scapula forwardsC7 spine ;arm abductio beyondT1-12 spines 90* Steadies scapulaRHOMBOIDES MINOR- Base of triangular area at Dorsal scapular Retraction of scapulaLigamentum nuchae root of spine of scapul nerve[c5]Spines c7-T1RHOMBOIDES MAJOR Medial border of scapula Dorsal scapular Retraction of scapula below of root of spine nerve[c5]LEVATOR SCAPULA
MUSCLE ORIGIN INSERTION NERVE ACTIONLEVATOR SCAPULA- Superior angle and Branch of dorsal Elevation of scapulaTransverse process upper part of medial scapular nerve[c5] Steadies scapulaof c1,2 border of scapula during armPosterior tubercles movementsof transverseprocess of c3,4
MOVEMENTS AROUND SHOULDER• Shoulder movements occur by coordinated motions of –1. Clavicular and sternoclavicular2. Acromioclavicular motion3. Scapulothoracic motion4. Glenohumeral motion
CLAVICULAR AND STERNOCLAVICULAR MOTION• At sternoclavicular joint,clavicle rises slow and steadiely 30* with 90* of arm elevation• Clavicular protraction ,retraction also occurs• the clavicle rotates 45* on its long axis during elevation of arm to full overhaed position180*. ACROMIOCLAVICULAR MOTION• It provides only two small arcs of motion about 15* during first and last 40* of arm elevation.• Clavicular rotation is essential for terminal arc mobility of acromioclavicular joint
SCAPULOTHORACIC MOTION• Its not a true joint but scapula glides freely on the loose aereolar tissue between two surfaces• Direction of movement described by acromian motion and sternoclavicular joint integrity• Rotation of scapula is facilitated by sternoclavicular and acromioclavicular joints
SCAPULA MOVEMENTS• Elevation - moving the superior border of the scapula and the acromion in an upward direction.• Depression - moving the superior border of the scapula and the acromion in an downward direction.• Upward Rotation - Moving the scapula so that the glenoid cavity faces upward. • Increases the ranges of motion during abduction and/or flexion of the shoulder.• Downward Rotation - moving the scapula so that the glenoid cavity faces inferiorly. • Increases range of motion during extension and / or adduction of the shoulder.• Protraction ( Abduction)- moving the scapula away from midline• Retraction (Adduction) - moving the scapula toward midline
SCAPULOTHORACIC MOTIONMOVEMENT MUSCLEVERTICAL PLANE Upper fibres of trapezius Infero lateral compartmentELEVATION Levator scapulaeDEPRESSION Lower fibres of serratus Infero lateral compartment anterior and p.minorHORIZONTAL PLANE Serratus anterior and Superomedial compart.PROTRACTION-moving pectoralis minor Seen in pushing oraway from vertical spine punching actionsRETRACTION-moving Rhomboides and middle Superomedialtowards vertical spine trapezoid fibres compart.seen in squarring of shouldersFORWARD ROTATION- Trapezius upper fibres Inferolateral compartmentoccurs in arm over head Serratus ant lower fibresabductionBACKWARD ROTATION Rhomboides and levator Inferolateral compartment scapula
GLENOHUMERAL MOTION• Arm elevation is classified by its plane of action• Flexion ,extension in SAGITTAL PLANE• Abduction adduction in CORONAL/FRONTAL PLANE• Medial and lateral rotations with a midflexed elbow• CIRCUMDUCTION-combination of different movements by which arm moves in circle
MOVEMENTS OF THE GLENOHUMERAL JOINT – Movements of the shoulder joint (glenohumeral joint) usually involve moving the humerus on the scapula. – All movements are to be studied starting from the ANATOMICAL POSITION – Axis of motion • Flexion - Extension – Coronal axis through head of humerus • Abduction /Adduction – Sagittal axis through humeral head • Rotation – Longitudinal axis through shaft of humerus
• Flexion moving the humerus forward and upward in the sagittal plane.• Extension - bringing the arm down to the side in the sagittal plane.• Abduction - moving the arm in the coronal plane away from the midline – Stage-initiate -supraspinatus 15*-90*- deltoid 90*-180* - deltoid with upward rotation of scapula• Adduction - moving the arm in the coronal plane towards the midline.• Inward Rotation - rotating the arm in a transverse plane so that the anterior surface of the bone turns inward.• Outward Rotation - rotating the arm in a transverse plane so that the anterior surface of the bone turns outward.
PRINCIPLE MUSCLES ACTING ON SHOULDERMOVEMENTS MAIN MUSCLE ACCESSORY MUSCLEFLEXION PECTORALISMAJOR(clavicular part) Coracobrachialis0-135* DELTOID ant fibres Biceps short headEXTENSION DELTOID post fibres Teres major45-60* LATISSMUS DORSI Triceps long head P major[sternocoastal head]ADDUCTION PECTORALIS MAJOR Teres major LATISSMUS DORSI coracobrachialis BICEPS long head TRICEPS short headABDUCTION SUPRASPINATUS[0-15*] DELTOID[15*-90*] SERRATUS ANTERIOR[90*-180*] TRAPEZOIDupper,lower fibres[90- 180]MEDIAL ROTATION PECTORALIS MAJOR subscapularis[INTERNAL] DELTOID ant fibres90* LATISSMUS DORSI TERES MAJORLATERAL ROTATION DELTOID posterior fibres[EXTERNAL] INFRASPINATUS
• Scapulohumeral Rhythm-Coordinated movements of the scapula and the humerus increasing the range of motion at the glenohumeral joint – Most noticeable during complete flexion and abduction of the shoulder – 2 * of humeral abduction is associated with 1* of scapula rotation• Humerus and scapula move in 2:1 ratio during abduction• For every 15* of elevation 10* occur at shoulder joint and 5* by scapular movements
• ABDUCTION-• Humeral head permits only upto 90*• By scapula rotaion making glenoid cavity facing ouwards the abduction range increased to 180• This is brought about serratus anterior and trapezius
REFERENCES• Text book of upperlimb-chaurasia• Operative orthopaedics-campbell• Hand book of fractures-zuckerman• Manual of clinical surgery-Das