Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
The Shoulder Complex - session 6 • Shoulder girdle and glenohumeral joint • Anatomy with a focus on muscle function • What can go wrong with the shoulder joint • Conditions such as tendinitis, rotator cuff tears • Management of these conditions Throwing action of the shoulder Muscular control Power and flexibility Positioning the hand in space Precision control of a weight Range of movement in yoga Hand behind to put a jacket on Hands behind your head Components of the shoulder complex • Consists of the scapula, clavicle and humerus • Responsible for moving the hand through space • Consider the functional units as the scapulothoracic joint (ST), sternoclavicular joint (SC), acromioclavicular joint (AC) and glenohumeral joint (GH) Shoulder girdle complex viewed from above • Note that the only joint attaching the shoulder girdle to the body is the SC joint • The clavicle acts as a strut – consider the implications of a fractured clavicle • Note also the angle of the clavicle with the frontal plane of the body • The angle of the scapula to the posterior plane of the body • The angle of the centre of the GH joint with the plane of the scapula Scapulothoracic joint • Not a true joint • It is separated from the thorax by a layer of interposed muscle – subscapularis muscle (cf later) • Movements of the scapula on the thorax are linked with movements of the AC and SCjts • The normal resting position of the scapula is 2” from the midline between the 2nd to 7th ribs • The shoulders should be level rather than sloping downwards Muscles associated with the scapular • The deep muscles are: • Levator scapulae – from transverse processes of C1-C4 cervical vertebrae to medial border of scapula between root of the spine of scapula and the superior angle – elevation and downward rotation • Rhomboids – R Minor from spinous process C7 + T1, R Major from spinous processes 2nd – 5th thoracic vertebrae to medial border of scapula between root of spine to inferior angle – retraction, elevation, downward rotation • Note - link between the cervical and thoracic spines and the scapula • The direction of the fibres of the rhomboid muscles and their ability to downwardly rotate the glenoid cavity. Over development produces downward sloping shoulders The superficial muscles • Trapezius – upper fibres from the occiput, ligamentum nuchae, 7th cervical vertebra to outer 1/3rd of clavicle and acromion – elevation – shoulder shrugging • Middle fibres – spinous processes 1-7 thoracic vertebrae to medial margin of acromion and superior lip of spine of scapula – retraction of scapula • Lower fibres – Spinous processes 6th to 12th thoracic vertebrae to apex of spine of scapula – with the upper fibres upward rotation of the glenoid • Serratus anterior – upper border of 1st- 8th or 9th ribs to pass under the scapula to insert along the medial border • Balance between the activity of each of the muscles is important to maintain the scapula in the correct position on the ribcage and in rotation of the scapula during GH movement. (cf later) Origin and insertion of serratus anterior • This muscle assists in rotating the inferior angle of the scapula outwards to tilt the glenoid cavity upwards • It also holds the medial border of the scapula against the thorax • With the hands under the shoulders against a wall or floor this muscle pulls the thorax backwards whilst performing a press up Summary of the movements of the scapulothoracic joint Nerves of interest associated with the scapula • The suprascapular nerve originates from the C4,5,and 6 cervical nerve roots. It passes through a bony notch on the superior aspect of the scapula. The nerve can be stretched and irritated if the scapula is habitually downwardly rotated Brachial plexus and the effect of shoulder depression • The brachial plexus is formed from the C5 – T1 nerve roots • These join to form the superior, middle and inferior trunks which pass over the first rib and under the clavicle • Depression of the shoulder girdle can pull on these structures causing pain and pins and needles in the distribution of the specific nerve affected Nerves in the axilla • The median and ulna nerves in the axilla have to be able to slide and glide to allow for movements of the shoulder and arm • cf elbow and wrist where the nerves can be involved in producing pain and dysfunction Sternoclavicular joint • The SC joint is a synovial plane joint • 2 saddle shaped surfaces one at the medial end of the clavicle the other formed by the manubrium of the sternum and the first costal cartilage • The surfaces are incongruent • There is an intra-articular disc and an interclavicular ligament • Anterior and posterior sternoclavicular ligaments and a joint capsule Movements of the SC joint • Movements of the SC joint occur with AC and ST movement • Elevation of the shoulder girdle produces roll and slide between the clavicle and the disc • At the end of range of elevation the costoclavicular ligament becomes taut • Depression of the shoulder girdle produces roll and slide in the opposite direction Movements of the SC joint in retraction and protraction • Retraction of the scapula is associated with roll and slide of the SC joint • The anterior ligament becomes tight at the end of the movement as does the costoclavicular ligament Acromioclavicular joint • • • • • Joins the scapula to the clavicle Plane synovial joint Superior aspect acromioclavicular ligament Fibrous capsule around the joint Coracoclavicular ligament binds the scapula to the clavicle Coracoclavicular ligament • 2 portions to ligament • Conoid – triangular thick ligament runs from underneath clavicle to knuckle of coracoid of scapula • Trapezoid – broad thinner ligament, upper surface of coracoid to inferior surface of clavicle • Role is to limit upward movement of clavicle • As scapula rotates outwards, coracoid moves away from the clavicle. • Creates increased tension in the ligament • Causes backward rotation of the clavicle via a crank shaft mechanism Movements of the AC joint • Posterior rotation as described previously with scapular motion • Slides and glides with elevation / depression, protraction / retraction of the shoulder girdle Capsule and ligaments • Large loose capsule – slack anteriorly and inferiorly. It allows 1” distraction of the head of humerus • Stability of the joint provided by ligaments and muscles • Glenohumeral ligaments reinforce the capsule anteriorly • 3 ligaments forming a ‘Z’ shape • The ligament becomes taut on lateral rotation • Coracohumeral ligament – from the coracoid blending with the superior aspect of the capsule • It restricts lateral rotation and gives passive support to the upper limb against gravity – when carrying a bag with the arm by the side Side view to show the subacromial space • The Coracoacromial arch forms an osteoligamentous structure protecting the head of the humerus, and the tendons and bursae which pass through the space • It prevents the head of the humerus (HOH) from dislocating superiorly • Note the origin of the tendon of the long head of biceps which also prevents upward dislocation of the HOH Contents of the subacromial space • Subacromial bursa – between the supraspinatus tendon (cf later) and the acromion • Permits smooth gliding between the humerus and supraspinatus tendon and surrounding structures • Supraspinatus – from the supraspinous fossa to superior facet, greater tubercle of humerus and joint capsule • Role to keep the head of the humerus centred in the glenoid with shoulder movement abduction (cf later) • Tendon passes through the subacromial space – vulnerable to rubbing and pinching or impingement • Infraspinatus – Infraspinous fossa to greater tubercle of humerus and shoulder joint capsule • Teres Minor – lateral border scapula to greater tubercle + capsule • Both produce lateral rotation + hold the HOH in the glenoid during movement of the shoulder • Subscapularis – subscapular fossa to lesser tubercle of humerus. • Medial rotation humerus + holding HOH into glenoid Rotator cuff muscles viewed from above • Looking from above with the subject lying on their back • Note the rotator cuff muscles surrounding the HOH • Balanced contraction of the muscles pulls on the HOH maintaining it in a central position whilst other muscles produce movements such as flexion Movements of the shoulder • The shoulder is a highly mobile joint allowing forward flexion/extension • Horizontal flexion – movement across the body, horizontal extension behind the body • Inward/medial and outward/lateral rotation with the arm into the side and at 90 degrees away from the body Combined movements • Hand behind head combines abduction and lateral rotation • Hand behind back combines extension, adduction and medial rotation Combined movements of the scapula and glenohumeral joint • When moving the shoulder from the starting position of hand down by the side forwards into flexion the scapula should remain still, stabilised by balanced activity of the muscles around the shoulder blade eg lower fibres of trapezius • The rotator cuff muscles hold the head of the humerus into the glenoid whilst the muscles acting on the shoulder joint produce the movement of flexion • At 45 degrees the shoulder blade rotates outwards tilting the glenoid upwards whilst the muscles producing flexion at the GH joint continue to move the arm forwards • When there are problems with the shoulder joint this finely balanced and co-ordinated pattern of movement is interrupted causing pain and reduced movement (cf later) • Coracobrachialis – from the coracoid to the humerus – flexes and adducts the shoulder • Pectoralis Major – from the clavicle, sternum and costal cartilages to the greater tubercle on the humerus – flexes, adducts and medially rotates the shoulder • Pectoralis Minor – superior surfaces of 3rd – 5th ribs to coracoid process of scapula. Tilts the scapula anteriorly. If tight it lifts the inferior angle of the scapula away from the chest wall – pseudo winging • Biceps Brachii – short head apex of coracoid, long head supraglenoid tubercle of scapula. Action at the shoulder is to produce flexion Deltoid muscle • Anterior fibres – from the lateral 1/3 of clavicle • Middle fibres – from the lateral margin of the acromion • Posterior fibres – spine of the scapula • Important prime mover of the shoulder but must work with the rotator cuff. If the rotator cuff does not hold the humerus centred in the glenoid, contraction of deltoid produces upward movement of the HOH • Latissimus Dorsi is a very powerful muscle originating from the thoracic spine, lumbar spine and back of the pelvis • It passes under the axilla (arm pit) to attach to the medial side of the humerus • This is the muscle used when walking with crutches to swing the body through • It is also used in skiing, paddling a canoe • If it is over dominant it can pull the shoulder downwards upsetting the fine balance of muscular action around the shoulder Prevalence • Shoulder pain is the 1/3rd most common condition in Primary Care • 16-26% of the population can be affected • Chronic or recurrent symptoms are common • Pain can be referred to the shoulder from the heart, diaphragm, gall bladder • Cancer of the apices of the lung and secondary bone metastases from breast cancer can also produce shoulder pain Classification of shoulder disorders • Stiff Frozen shoulder Arthritis • Weak Rotator cuff disorders – tendinitis, tendinosis • Unstable Traumatic vs non-traumatic instability • Acromioclavicular joint disorders Stiff shoulder • Affects women > men, age 40-60, diabetics and immobilisation post surgery more at risk • ? Inflammatory response with fibrosis and contracture of the capsule • Restriction of all active and passive movements • Stage 1 – pain at rest and extremes of motion, disturbed sleep, unable to lie on affected side (2-9 months) • Stage 2 – pain may ease, progressive stiffness (4-12 months) • Stage 3 – gradual improvement in function and motion (5-26 months) • A steroid injection in the early stages can help to reduce the pain • PT may help if judicious and does not aggravate pain. Manual therapy and specific exercises to increase movement • Arthrographic distension of the capsule to break adhesions • If not resolving - MUA and steroid injection or arthroscopic release of the capsule Arthritis of the Glenohumeral joint • Loss of joint space, osteophyte formation, note the reduced subacromial space - ? rotator cuff involvement • Mild cases – rest, NSAIDs/analgesia, ROM & rotator cuff strengthening exercises • Moderate - severe -Refer on for assessment of rotator cuff and ?arthroplasty -?suprascapular nerve blocks DO NOT INJECT Example of shoulder joint replacement • There are a range of different prostheses depending on the presentation and the surgeons preferences • Post operatively rehabilitation will be required to increase muscle strength and restore range of movement Weakness of the shoulder • 35-75 years: rotator cuff tendinosis, subacromial bursitis, rotator cuff tear, “subacromial impingement” • Collagen degeneration → tendinosis • Fibroblasts accumulate, collagen disorganised → weakened muscle • Cuff dysfunction - ↓ HOH centring • 2° extrinsic compression • Reactive changes to bursa, bone spur formation, coracoacromial thickening • Cuff tear extends slowly or rapidly with minor trauma • Tendon retracts but capsule retracts • Grey hair equals cuff tear, white hair equals large cuff tear • Full thickness tears found in 50-80% of asymptomatic 70-80yr olds (Milgrom et al, 1995) Management • Poor correlation between diagnostic investigations such as U/S, MRI, examination findings and orthopaedic tests and underlying cause of shoulder pain and dysfunction • NSAIDs/ analgesia • Relative rest/activity modification advice very important if the condition is irritable • Physiotherapy - tendinopathy → massive tears, graduated specific exercises to load the tendon progressively, increase muscle strength and restore normal shoulder movements • Consider subacromial cortisone injection if pain hindering rehabilitation • This may also reduce tenocyte numbers as tenocyte proliferation has been associated with tendinopathy • Steroid injection may help to restore tendon cellular haemostasis • Sudden severe pain with marked loss of movement • Rest, ice, analgesics, NSAIDs. Consider subacromial lignocaine injection. Avoid steroid injection. Needling and aspirating the calcium deposit may relieve pain • Calcification is often seen in the rotator cuff tendons as part of the normal degenerative process Glenohumeral instability Types of dislocation • The head of the humerus can dislocate anteriorly or posteriorly depending on the type of injury and the position of the arm • It most commonly occurs after a fall onto an outstretched arm • If the humerus dislocates anteriorly the normal outline of the shoulder is lost with a squared off appearance • The dislocation is reduced followed by rehabilitation to restore the function of the rotator cuff muscles, increase strength and range of movement of the shoulder • Atraumatic Subluxation – 6/12 rehab before referral on to consider surgery Acromioclavicular joint injury • Caused by a fall onto the point of the shoulder • Sprains to moderate displacements of the joint are treated conservatively with rest, analgesia, shoulder girdle exercises • Significant injuries with instability of the clavicle due to involvement of the conoid and trapezoid ligaments should be referred to orthopaedics for surgical intervention Next week • Elbow joint structure and function • Superior and inferior radio-ulna joints • Common conditions such as tennis elbow, golfers elbow • Linkage with the radial nerve, ulnar nerve and cervical spine • Presentation and management of conditions