7. Shoulder Flashcards
Clavicle (collar bone)
Superior surface is smooth
• Acts like a strut – holds out shoulder and scapula joints
• S-shaped curve – provides strength
Sternoclavicular joint:
—> synovial joint between sternim and clavicle
• Synovial joint
• Allows movement
• Articular disc – acts as a shock absorber
Clavicle dislocation
Dislocations (when clavicle pops out of joint) are rare due to ligaments
Inferior surface of clavicle
Inferior surface is rough
• Due to the attatchments – of costoclavicular ligaments, subclavius muscle attatch at, attachment of coracoclavicular ligmaent
Acromoclavicular joint
–> between acromion and clavicle
• plane type of synovial joint
• Supported by acromoclavicular and coracoclavicular ligaments
• Note Subclavian groove = site of attachment of subclavius muscle
• Suspend the upper limb from clavicle – scapula hangs from the clavicle
Scapula (shoulder blade)
- Triangular & flat
* Overlies ribs – posterior ribs 2nd - 7th rib
Scapula Posterior surface
- spine of scapula
- supraspinous fossa (above spine)
- infraspinous fossa (below spine)
Borders of scapula
• Medial border – by thoracic spine
Superior border: suprasternal notch
Angles of scapula
• Superior, inferior and lateral angles
• Lateral angle = head of scapula and small and shallow glenoid cavity
• The lateral angle has head of scapula
– Small & shallow glenoid cavity
Spine of scapula
• Spine continues laterally as acromion = point of shoulder
Anterior concave surface of scapula
- Subscapular fossa
- Coracoid process – like a bent finger pointing to shoulder
- Concave surface as it contour the ribs
Proxiaml humerus
Basic structure
Spherical head and 2 necks • Greater tubercle laterally • Lesser tubercle anteriorly • Intertubercular (bicipital) groove – contains tendon of long head of biceps • Between greater and lesser tubercle
- Laterally Deltoid tuberosity – site of attatchment of deltoid muscle
- Posteriorly oblique radial (spiral) groove – radial nerve and profunda brachii artery
Proximal humerus - • Anatomical neck
– proximal to tubercles
– joint capsule
Between head and tubercles
Proximal humerus - • surgical neck
– distal to tubercles
– common site of fractures
Glenohumeral joint
• Synovial / Ball and socket = between humerus and scapula
- Cavity accepts approx. 1/3 of humeral head (not as deep of a socket)
- Deepened by fibrocatilaginous labrum - rotator cuff
- Joint capsule (lined by synovium) – margin of glenoid cavity (attach medial) & anatomical neck (attach lateral)
- Inferior part of capsule = weakest area
Glenohumeral joint – openings
• 2 openings
– between tubercles of humerus
• Tendon of long heads of biceps brachii
– anteriorly – communication with subscapularis bursa
• Glenohumeral Joint ligaments
– 3 fibrous bands reinforce anterior capsule (reinforce joint)
• 3 bands = superior, middle and inferior
• Coracohumeral ligament
- From greater tubercle to coracoid process
* Superir to joint
• Coraco-acromial arch
– 2 bones and Coraco-acromial ligament (corcoid process, acromion and corcoid ligament)
– strong
– prevents superior displacement of head
Tendon, bursa arch
• Supraspinatus passes under arch
• Subacromial bursa facilitates movement of
– Supraspinatus tendon
- deltoid
7 Movements at glenohumeral joint
- Flexion
- Extension
- Abbduction
- Adduction
- Medial rpotation
- Lateral rotation
- Circumduction
Shoulder abduction
When abbducted to 90 degrees, when abducted iwhtout rotation greater tubercle with contact with corcoid arch to stop further abduction – but if you rotate laterally you can have further abbduction
Movements at “scapulothoracic” joint:
–> joint between scapula and thoracic wall
• Elevation and adepression
• Protration (forward)
• Upward and downwards rotation
Initial movements can occur without scapular motion
5 Fascia of upper limb
- Superficial fascia is subcutaneous tissue
- Deep Fascia
- Clavipectoral fascia (deep to pec major)
- Deltoid fascia
- Brachial fascia
• Deep Fascia
• Pectoral fascia invests pectoralis major
– continuous inferiorly with fascia of abdominal wall & laterally axillary fascia (floor of axilla)
• Clavipectoral fascia (deep to pec major)
– Descends from clavicle
– encloses subclavius and pectoralis minor
– inferiorly suspensory ligament of axilla (pulls axilalry fasica & skin upward during abduction of the arm to form the armpit) - it suspends/ supports axilalry fascia
• Deltoid fascia
○ Covers muscles that cover shoulders and scapula
• Brachial fascia
– encloses arm inferiorly like a sleeve
– continuous into ther forearm as the antebrachial fascia
Muscles of the proximal upper limb
2 regions
- Pectoral Region
* Shoulder Region
• Pectoral Region
• Anterior chest wall
• Shoulder Region
- Intrinsic: originate from scapula and/or clavicle, and attach to humerus
- Extrinsic: originate from torso, attach to bones of shoulder
Pectoral muscles: pectoralis major
Large, fan shaped
- P: Clavicular head
- Sternocostal head - arise from sternum and upper costal cartillages
- D: Lateral lip of intertubercular sulcus of humerus (between grater and lesser tubercles)
- I: Lateral & Medial pectoral nerves
• Action : Adduct & Medially rotate humerus
Pectoral muscles: pectoralis major
Laterally forms
- pec major forms Anterior wall of axilla
- Deltopectoral groove – where cephalic vein runs
- Clavipectoral (deltopectoral) triangle – deltoid ,pectoralis major and clavicle
Pectoral muscles – pectoralis minor
• Triangle shaped
- P: 3rd-5th ribs anteriorly
- D: Coracoid process of scapula
- I: Medial pectoral nerve (C8, T1)
- Action: Helps stabilise scapula
- Can help with inspiration – by elevating ribs
Pectoral muscles: subclavius
- P: 1st rib
- D: Inferior surface of middle of clavicle
- Innervated by its own nerve : Nerve to subclavius (C5, C6 from root)
- Action: Anchors and depresses clavicle
- Stabilise sternoclavicular joint
Pectoral Muscles: Serratus anterior (L. serratus, saw)
• forms Medial wall of axilla
- P: Lateral parts of 1st-8th ribs
- D: Medial border of scapula
- I: Long thoracic nerve (C5, C6, C7)
Muscle attaches to medial edge
• Action : On the scapula
– Protracts
– Anchors scapula against wall
– Rotates (inf part)
Extrinsic shoulder muscles – trapezius
Large muscle
• 3 parts – superiod/descending, trasnvers/middle, assencding/middle
- P: Skull, nuchal ligament & spinous processes of thoracic vertebrae,
- D: clavicle, acromion & spine of scapula
- I: Spinal accessory (CN XI) and some C3, C4
Extrinsic shoulder muscles – trapezius
Action?
– Middle (or all together) retract scapula
– Descending elevates
– Ascending depresses
– Ascending and descending work in different directions and so they rotate glenoid cavity
Extrinsic Shoulder Muscles: Latissimus Dorsi (L. Widest of back)
• Large fan shaped
- P: Spinous processes of lower thoracic vertebrae (T6-12), thoracolumbar fascia & iliac crest
- D: Floor of intertubercular sulcus of humerus
- I: Thoracodorsal nerve (C6, C7, C8)
• Action: Extends, adducts, medial rotates humerus
Latissmus dorsi is between pec major and teres major
Extrinsic Shoulder Muscles: Levator scapulae
• Strap muscle
- P: Transverse processes of C1-C4 vertebrae
- D: Superior/ Medial border of scapula
- I: Dorsal scapular (C4,5)
- A: Elevates (or fixes) scapula and rotates glenoid cavity inferiorly
- Can contribute to neck movements
Extrinsic Shoulder Muscles: Rhomboids
Deep to trapezius (Major is 2x wider)
2 rhomboids one each side
- P: Spinous processes of C7 -T5
- D: Medial border of scapula
- I: Dorsal scapular (C4,5)
Extrinsic Shoulder Muscles: Rhomboids
Action
• Action : On scapula
– Retract
– Fix scapula to thoracic wall
– Rotate glenoid cavity inferiorly
Intrinsic Shoulder Muscles: Deltoid
• Forms rounded contour of shoulder – looks like an innverted delta
- P: Lateral clavicle, acromion and spine of scapula
- D: Deltoid tuberosity of humerus
- I: Axillary nerve
Intrinsic Shoulder Muscles: Deltoid
Action?
– Anterior: flexes and medially rotates arm (helps pec major)
– Posterior: extends and laterally rotates
– Middle: abducts arm (also if all together)
Anterior and posterior – swinging movement when walking
Note abduction:
supraspinatus initiates first 15degrees
Then deltoid helps with abduction of arm
Axillary nerve (C5,6)
Supplies
• Deltoid
• Regimental skin patch overlying it
Fracture at axillar neck and result in axillary nerve palsy
Intrinsic Shoulder Muscles: Teres Major
• Part of post axillary fold
- P: Post surface of inferior angle of scapula
- D: Medial lip of intertubercular sulcus of humerus
- I: Lower subscapular nerve (C5, C6)
- Action: Adducts and medially rotates
- Helps with extension
Extrinsic shoulder muscles
Trapezius
Latissmus dorsi
Levator scapulae
Rhomboid
Pectoral muscles
Subclavius
Pec minor
Pec major
Serratus anterior
Intrinsic muscles
Deltoid
Teres major
Rotator Cuff Muscles - names. SITS
- Supraspinatus
- infraspinatus
- Teres minor
- Subscapularis (inserts anterior to lesser tuberlce, the other 3 insert into greater tibercle)
Rotator Cuff Muscles
Purpose
- 4 muscles that originate from scapula and attach to humeral head – from rotator cuff
- Reinforce joint capsule
- Muscles ‘pull’ humeral head into glenoid fossa
- => Protects joint & gives it stability
Rotator Cuff Muscle: Supraspinatus
Not actually a rotator but is an abductor
- P: Supraspinous fossa of scapula
- D: (Superior facet of) greater tubercle of humerus
- I: Suprascapular nerve (C4,5,6)
• A:
– Initiates (0-15o)
– Assists deltoid (15-90o) In Abduction
Rotator Cuff Muscle: Infraspinatus
- P: Infraspinous fossa of scapula
- D: (Middle facet of) greater tubercle of humerus
- I: Suprascapular nerve (C5,6)
• A: Laterally rotates arm
Artery goes over and nerve goes under
Rotator Cuff Muscle: Teres Minor
• Sometimes difficult to distinguish from infraspinatus
- P: Middle part of lateral border of scapula
- D: (Inferior facet of) greater tubercle of humerus
- I: Axillary nerve (C5,6)
• A: Laterally rotates arm
Traingular interval – that profunda brachii and radial nerve pas through
Rotator Cuff Muscle: Subscapularis
• Forms part of posterior wall of axilla
- P: Subscapular fossa
- D: Lesser tubercle of humerus
- I: Upper and lower subscapular nerves (C5,6,7)
• A: Medially rotates arm
Arm compartments
- Medial and lateral intermuscular septa extend from deep surface of brachial fascia and attach to to humerus
- Divide arm into anterior (flexor) and posterior (extensor) compartments
Anterior Compartment:
Proximal
• P: 2 heads from scapula
– Short: Coracoid process
– Long: Supraglenoid tubercle (superior to glenoid cavity)
• Long tendon crosses within cavity of joint (surrounded by synovial membrane), descends in intertubercular sulcus
Anterior Compartment:
Distal
• D: Bellies of the 2 heads unite in middle of arm.
2 insertions of the muscle
– tuberosity of radius via biceps tendon
– fascia of forearm via bicipital aponeurosis
Anterior Compartment:
Innovation
Tan – tendon, artery, nerve
• Bicipital aponeurosis crosses tendon and nerve
• I: Musculocutaneous nerve (C5,6,7)
Anterior Compartment:
Action
– Forearm supinated (palm upwards): flexor of elbow (like when carrying a tray)
– Elbow flexed & forearm pronated(palm down): powerful supinator (like when screwing a screw tight)
Anterior Compartment: Brachialis
- P: Distal half of anterior humerus (large areaa of attachment)
- D: Coronoid process and tuberosity of ulna
- I: Musculocutaneous nerve (C5,6) and radial nerve
Biceps inserts into radius
Brachialis inserts into ulna
• A: Most important elbow flexor – in all positions and movements
Anterior Compartment: Coracobrachialis
- P: Coracoid process of scapula
- D: Medial surface humerus (near nutrient foramen & at level of the deltoid tubercle)
- I: Musculocutaneous nerve (C5,6,7) – pierces it
- A: Helps flex and adduct arm and shoulder
- Cause a pthology if it compresses neurovascular structures in arm
Posterior Compartment: Triceps Brachii Fusiform
• P: 3 heads
– Long: arises form Infraglenoid tubercle of scapula
– Lateral: arise from posterior surface of humerus and attach superior to radial groove
– Medial: arise from posterior surface of humerus and attach superior inferior to radial groove
• D: Olecranon of ulna
- I: Radial nerve (C6,7,8)
- A: Extend elbow
Posterior Compartment: Anconeus
Small • Usually partially blended with medial head of triceps • P: Lateral epicondyle of humerus • D: Lateral surface of olecranon • I: Radial nerve (C7,8, T1)
• A: Assists in extending forearm/ stabilises joint
Posterior compartment
innervation
Radial nerve
Brachial Artery
- Continuation of axillary artery – inferior border teres major
- starts Medial to humerus, then anterior
- Divides into radial and ulnar arteries – under bicipital aponeurosis
Supracondylar fracture
Supracondylar fracture – in young children = damage brachial artery and no pulse distal to it.
Brachial artery _ branches
- Profunda brachii artery
- Humeral nutrient artery
- many muscular branches
Superior Ulnar collateral artery
anastomoses with posterior ulnar recurrent
• Inferior Ulnar collateral artery
anastomoses with anterior ulnar recurrent
Profunda Brachii Artery
Supplies posterior compartment muscles
• Accompanies radial nerve in radial groove
Complex branching into
• Radial Collateral A: continues with radial nerve anterior to septum and lateral epicondyle, anastomoses with radial recurrent artery
Collateral and recurrent arteries form a peri- articular anastomoses of the elbow
– allows blood to reach forearm even when flexion compromises flow in distal brachial artery
Musculocutaneous Nerve
- Supplies all 3 muscles of anterior compartment (BBC)
- Biceps
- Brachialis
- Coracobrachialis
- Pierces coracobrachialis
- Continues between biceps and brachialis (anterior to brachialis)
- Emerges lateral to biceps as lateral cutaneous nerve of forearm
Median nerve
- start Lateral to artery, crosses to medial side at midpoint of arm
- Lies deep to bicipital aponeurosis in cubital fossa
Ulnar nerve
- Medial to artery ‘
- Middle of arm, pierces medial intermuscular septum (to go from anterior to posterior compartment)
- Descends between septum and triceps
- Passes posterior to medial epicondyle
Radial nerve
• Supplies all muscles in posterior compartment
• Posterior to artery
• Early branches to long and medial heads
Continuation of posterior cord of brachial plexus
• Through Triangular Interval
– Inferior to teres major
– between long head of triceps & humerus
- Descends inferolaterally in radial groove (profunda brachii)
- Muscular branches
- Pierces lateral intermuscular septum
- Divides into deep and superficial branches
Veins
Basilic and cephalic vein pierce deep fascia
Cephalic vein pierces the clavy pectoral fascia to become deep
6 Common conditions of the shoulder
- Dislocation
- Clavicle fracture
- Impingement
- Calcific supraspinatous tendonitis
- Adhesive capsulitis (‘frozen shoulder’)
- Osteoarthritis
Shoulder dislocation
• Common shoulder pathology presenting at the Emergency department with pain and visible deformity
○ But it can easily be missed
. Shoulder stability
- Suction cup effect of the labrum around the humeral head
* Negative intra-articular pressure within the joint
Static stabilisers
- Static stabilisers – glenoid labrum, joint capsule, ligaments
- Dynamic stabilisers – rotator cuff muscles, biceps
Directions of dislocations
- Anterior = most common
- Posterior
- Inferior
- 60% risk of recurrence overall
- Risk decreases with age
Anterior dislocation - how it happens
Occurs when
• Usually occurs when the arm is abducted and externally rotated ( hand behind head position)
• External force on the arm in the posterior direction pushing the head antero-inferiorly
OR • Direct blow to the shoulder from posteriorly
Anterior dislocation - subcoracoid
• Subcoracoid– the humeral head sits anterior and inferior to the coracoid (60%)
Anterior dislocation - subglenoid
• Subglenoid (anteroinferior) – humeral head is inferior and slightly anterior to the glenoid. The head also migrates medially (adducted bump, down)
Clinical presentation of anterior dislocation
Loss of shoulder contour – not smooth round
Arm is slightly abducted and forearm internally rotated
Contra-lateral hand supports affected arm
Posterior dislocation - mechanisms of injury
• Violent shoulder contraction - Epileptic seizure - Electrocution - Lightening strike • Blow to anterior shoulder • Arm flexed across body and pushed posteriorly
Clinical presentation of posterior dislocation
- Squaring of the shoulder
- Arm adducted and internally rotated
- Prominent coracoid process
- Humeral head may be prominent posteriorly – so you can feel the coracoid or feel humerul head on the back
Scapular view
- Humeral head should normally be at the ‘ glenoid (bifurcation of the Y)
- Normally this would be to painful for patient
- Head is out
Inferior dislocation
- Rare – 0.5% of cases
- Hyper abduction injury
- High incidence of associated injuries:-
- Nerves 60%
- Rotator cuff 80%
- Vascular 3%
Head moves down into brachial plexus in axilla
Associated injuries with dislocations
- Fractures in approximately 30% of cases – humeral head, greater tuberosity, clavicle
- Hill Sach’s lesion – 2/3 compression of the humeral head posterolaterally
- Bankart’s lesion – capsule/labral disruption from the glenoid
- Glenohumeral damage
- Rotator cuff injury – more common in elderly
- Nerve injury – most commonly the axillary nerve
- Vascular injury – axillary artery (rare)
Treatment of clavicle fractures
- Most treated nonoperatively with a sling or cuff and collar
- Sling given if fracture is more distal
• Some need surgical fixation
- Displacement with tenting of the skin
- Open fracture
- Neurovascular compromise
- Floating shoulder
- Muscle interposition – if muscle is in the way bones can’t heal
Complications of clavicle fractures
• Non-union • Malunion • Infection (open fracture) • Nerve damage - Suprascapular - Supraclavicular - Trunks and divisions of brachial plexus • Vascular – subclavian vessels • Pneumothorax
Rotator cuff tears
Acute (trauma) /Chronic (degenerative microtrauma)
• Supraspinatous is the most commonly one involved as it is under the coraco-acromial arch
Rotator cuff tears- risk factors
• Age • Recurrent overhead activity - Painters - Athletes – swimming, tennis,weightlifting
- Shoulder osteoarthritis with osteophytes = rub on cuff to give a tear
- Acromial shape variants
Supraspinatous tears - clinical presentation
• Can be asymptomatic
• Most commonly – anterolateral shoulder pain radiating down the arm
• Worsened by activity (present at rest)
- Overhead activity
- Leaning on the elbow/pushing out of a chair (displaces the shoulder superiorly
- Reaching forward
• May complain of weakness of shoulder abduction
Supraspinatous tears - treatment
- Treatment depends on symptoms and underlying pathology
* Variable - physiotherapy, injections (to relieve pain), arthroscopic /open repairs and grafts
Impingement syndrome
Bony and soft tissue injury
• Involves supraspinatous impinging on the undersurface of the coraco-acromial arch
Impingement syndrome
Causes
• Caused by anything that narrows the subacromial space
- Thickening of the coraco-acromial ligament
- Inflammation of supraspinatous tendon
- Subacromial osteophytes
Impingement syndrome
Treatment
Treatment – can be surgery and physiotherapy
Calcific supraspinatous tendonitis
- Deposition of hydroxyapatite crystals in supraspinatous tendon
- Pain on abduction / flexion of the shoulder - Reduced coraco-acromial space
Calcific supraspinatous tendonitis
Clinical symptoms
- Stiffness
- Snapping sensation
- Catching of muscle
- Reduced range of movement
Pathology – calcific tendinitis
- Theory 1
- Regional hypoxia
- Tenocytes –>chondrocytes
- Endochondral ossification
- Theory 2
- Metaplasia of mesenchymal stem cells into osteogenic cells
- Ectopic bone formation
- Crystalline in the resting phase
- Reabsorbed by phagocytes (‘toothpaste’)
- Reabsorption phase most painful
Calcific supraspinatous tendintis
4 stages
Pre-calcific –> Formative –> Resorptive –> Postcalcific
During the resorptive phase it is reabsorbed by phagocytes becoming ‘toothpaste’ like. This is the most painful phase.
Calcific supraspinatous tendintis treatment
• Non-operative
- NSAIDs, physical therapy, steroid injections
- Extra-corporeal shock-wave therapy
- Ultrasound guided needle lavage/barbotage = use needle to squeeze them out
• Operative - Surgical decompression of calcium deposit
Adhesive capsulitis ‘Frozen shoulder’
- Disabling condition involoving the glenohumeral joint which is stiff and inflammed
- Very painful takes about 2 years to fix on its own
Adhesive capsulitis – diagnostic criteria (Codman)
- Global restriction of shoulder movement
- Idiopathic aetiology
- Usually painful at the outset
- Normal x-ray
- Limitation of external rotation and elevation
Adhesive capsulitis Risk factors
- Female – 4th/5th decade
- Shoulder trauma
- Epilepsy
- Cardiac/lipid anomalies
- Diabetes mellitus (x2-4 increased risk)
- Endocrine disease
- particularly hypothyroidism
- Drugs
Adhesive capsulitis - treatment
- Analgesia
- Physiotherapy
- Distension injections – needle into joint and inflate it
- Steroid injections – relieve inflammation and help pain
- Manipulation under anaesthesia
- Arthroscopic/open release
Adhesive capsulitis - stages
- 3 stages over an average of 2 years
• Freezing (3 months)
• Frozen (3-9 months, pain at extreme range of movement and marked stiffness)
• Thawing (9-18 months, painless and stiff – starts to resolve so start therapy)
90% of shoulder motion regained
glenohumeral and acromioclavicular joints
Glenohumeral Arthritis
• More common in women and increases with age
Causes of secondary Osteoarthritis
- Post-traumatic
- Post dislocation
- Inflammatory / crystalline arthritis
- Osteonecrosis
- Neuropathic
- Rotator cuff arthropathy
Acromioclavicular Arthritis
—> Due to transmission of large axial loads through a small contact area causing repetitive microtrauma • More common with age but can occur in second decade
Acromioclavicular Arthritis
Risk factors
- Trauma
- Distal clavicle osteolysis
- Inflammatory arthropathy
- Post-infection
- Associated with individuals who perform increased overhead activities eg weight lifters/sportsmen
Osteoarthritis treatment
• Activity modification • Analgesia • Steroid injections • Surgery - Excision of distal clavicle (AC joint) - Arthroplasty (Glenohumeral)
