Download The-shoulder-session-6

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
•
•
•
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•
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