Wk 1: functional anatomy and biomechanics of the shoulder girdle complex Flashcards
where does the shoulder girdle articulate?
sternum
the shoulder is…
the most mobile joint in the body
what is the alignment of the ligaments of the shoulder girdle?
vertically aligned & small
what does the shape and alignment of the ligaments affect?
decreases stability
what does optimal function of the shoulder complex require?
- optimal positioning of all joints
- ideal excursion/ mobility of all joints
- motor control of all joints
what does movement of the shoulder complex require smooth inter-relationships between?
- humerus and scapula
- scapular and clavicle
- clavicle and sternum
humerus and scapula relationship
humerus rotates about the scapula within the GH jt
scapula and clavicle relationship
scapula rotates about the clavicle at the AC jt
clavicle and sternum relationship
clavicle rotates around the sternum at the SC jt
what is the scapula resting position over the ribs?
concave
what does the scapulo-thoracic articulation provide?
base for GHJ stability & mobility
what does the scapulo-thoracic articulation act as?
muscle attachment site between shoulder complex and thoracic/ cervical spine.
what does the scapulo thoracic articulation transfer?
loads from upper limb to torso and vice versa
what ribs does the “ideal” scapular resting position sit?
between T2 and T7
how far from the thoracic midline is the ideal scap resting position?
approx 7 cm
position of the scapula
- slight UR (3)
- slight anterior rotation / tilt (8)
- internal rotation of 30
what does the ‘ideal’ scapular resting position provide?
stable, safe socket for GH jt and prevents inferior subluxation
what is the sequence of shoulder girdle movements that makes up scap UR
- scap rotates upwardly as clavicle elevates around an AXIS OF MOTION that passes through the SC jt and base of scapular spine
- clavicular elevation continues until costoclavicular ligament becomes tight. Axis of scapular upward rotation motion moves to AC jt
- the scapula continues to rotate upward at AC jt UNTIL CC ligament BECOMES TIGHT
SCAPULAR UR CONTINUES
what does tension in the coracoclavicular ligament produce?
a passive force that rotates the clavicle backwards
what does backward clavicular rotation do to the clavicle?
elevates the distal end of the clavicle and, with it, the acromion and the AC jt
what does the elevation of the distal clavicle due to backward rotation, do?
enables last few degrees of abduction
what allows continued scapular UR?
elevation of the acromion and AC jt
what does full shoulder motion require?
- thoracic extension 10-15
- rib cage mobility
- trunk/ LL strength, stability and flexibility
what does optimal function require?
- correct posture that then produces –>
- optimal length tension relationships of muscles and articular structures
what are the static/ passive stabilisers of GH stability?
- bony geometry
- glenoid labrum
- glenoid depth and orientation
- vacuum effect
- capsuloligamentous structures
what are the active stabilisers of GH stability?
neuromuscular system
what does synovial fluid in the GH jt do?
creates a wet surface between the humeral head & glenoid fossa –> keeps suction effect strong
what is the glenoid labrum?
firbo-cartilaginous tissue that deepens glenoid by 9mm superior to inferior and 2.5mm antero-posterior
what does the glenoid labrum increase?
articular surface area by 50% / adapts to accomodate movement of the HOH
what does the glenoid labrum allow for?
for attachment of GH ligaments, cuff tendons and LHB
what is the adhesion-cohesion bond?
when 2 wet surfaces come into contact with each other this creates an adhesion-cohesion bond, which provides stability to the GH articulation - compresses HOH into socket –> seals labrum and glenoid to humerus
what does negative intra-articular pressure in the GH jt do?
helps to resist anterior and superior HH translation
what does negative intra-articular pressure in the GH jt require?
intact glenoid labrum/ capsule = critical component
where does the GH capsule attach?
around glenoid rim and forms a sleeve around HOH and anatomical neck
where does the inferior position of the GH capsule lie?
in folds – important in laxity and adhesive capsulitis
what is the GH capsule reinforced by?
ligaments and RC tendons
what is the posterior GH capsule intimately reinforced by?
rotator cuff tendons (IS and TM)
what does the posterior GH capsule restrains?
flexion, abduction, IR (stops excess)
what does the superior and middle posterior capsule restrain?
IR
what does the inferior aspect of the postrior capsule restrain?
abduction +/- IR
GH ligaments
- coracohumeral ligament
- superior GH ligament
- middle GH ligament
- inferior GH ligament
what restrains 0* abduction
CHL and SGHL
what restrains 45-60* abduction
MGHL
what restrains 90* abduction
IGHL
what do the GH ligaments do?
guide and position the HOH
CORACOHUMERAL LIGAMENT
where does the CH ligament attach?
anterolateral base of the coracoid
how many bands are in the CH ligament?
2
what ligament is difficult to separate from the CH ligament
superior GH ligament
what does the CH ligament blend with?
the capsule
what does the CH ligament insert into?
and inserts into the greater and lesser tuberosities
functions of the CH ligament?
- helps support the dependent arm
- resists inferior subluxation of the GH
- becomes taut in external rotation
(ANTERIOR) SUPERIOR GLENOHUMAL LIGAMENT
where does the ligament start?
from tubercle of glenoid, anterior to HOH lesser tuberosity
SUPERIOR GH LIGAMENT
where does the ligament extend to?
HOH lesser tuberosity
MIDDLE GH LIGAMENT
where does it extend laterally and inferiorly?
supraglenoid tubercle/ anterior/ superior aspect of labrum
SUPERIOR GH LIGAMENT
what does the ligament provide?
resistance to inferior subluxation
MIDDLE GH LIGAMENT
what muscle does it blend with and where?
subscapularis @ 2cm medial to insertion
where does the middle GH ligament insert in?
lesser tuberosity
what are the dimensions of the middle GH ligament?
2cm wide, 4mm thick
what does the middle GH ligament contribute to?
restraint of anterior humeral displacement
where is the middle GH ligament taut?
45* abduction with ER (stop sign)
INFERIOR GH LIGAMENT
what does it form, along with 2 other things?
inferior sling
3 parts of the inferior GH ligament
anterior-inferior, inferior, posterior-inferior
where is the inferior GH ligament attached to?
entire anterior labrum, humeral articular surface and anatomical neck
what is the inferior GH ligament involved in?
maintaining anterior and inferior stability
FUNCTIONAL ANATOMY AND BIOMECHANICS OF THE SHOULDER GIRDLE COMPLEX PART 2
what are the dynamic stabilisers of the shoulder?
rotator cuff muscles
how does the shoulder give proprioception ?
nerve fibres & mechanoreceptors localised in the capsule tissue - form part of a physiological feedback mechanism
how many muscles move and stabilise the scapula
15
how many muscles provide for GH jt motion
9
how many muscles support the scapula on the thorax?
6
what muscles make up the ‘force- couple’ of the scapula?
trapezius and SA
what does the ‘force- couple’ of the scapula do?
UR the scapula to adequately position glenoid for the humeral head–> keep glenoid fossa in good position to prevent inferior subluxation of humeral head
how does the ‘force-couple’ keep the scapula in adequate positoin?
SA synergises traps to keep anterior surface of scapula on rib cage
what are the 3 different roles of the RC?
- anticipatory function (feed forward)
- rotator cuff muscles maintain the humeral head centred within the glenoid in an anterior/ posterior and superior/ inferior direction/ IR and ER
- torque production - IR/ER
3 functions of the RC?
- vaccum effect that pulls the humeral head into the glenoid
- feed forward function (anticipation)
- keeps the HH centred in the glenoid
what are the other muscles that contribute to the RC?
- LHB
- subscap
- deltoid
how do the LHB and the subscap contribute to RC?
act as a pulley system and prevent anterior subluxation (45* abduction)
what does the LHB tendon do in the RC?
torsioned in groove in elevation and pulls on labrum
what divides the SC jt into 2 portions?
intra-articular disc
how many axes of movement does the SC jt move?
3
what are the movements of the SC jt?
- elevation/ depression around oblique axis (45 up, 10 down)
- anterior/ posterior rotation (30-35*)
- axial rotation (45*)
what are the consequences of SC jt dysfunction?
- degeneration (minimal impairment)
- dislocation (unusual as ligaments are very strong)
- laxity of SC ligaments (resting clavicle on 1st rib)
what happens to the clavicle during elevation of the scapula?
clavicle rotates upward on the sternum and produces an inferior glide to maintain jt contact
AC JT
3 axis of rotation
- longitudinal (protraction/ retraction) 30*
- transverse (frontal plane) - elevation/ depression 60*
- transverse (sagittal plane) 30*
AC JT
consequences of dysfunction
- disease / ossification
- limited shoulder movement
- symptoms may be indistinguishable to sub-acromial pathologies
what are the shoulder girdle articulations?
- scapulothoracic jt
- glenohumeral jt
- acromioclavicular jt
- sternoclavicular jtwha
what are the 3 phases of scapulohumeral rhythm
- early
- mid
- late
shoulder functional actions?
- allows us to position our hands in space
- throw effectively
- push, pull, lift, carry
what are the components of the interview/ history?
- initial interpretation
- establish red/ yellow flags
- goal setting
- develop hypothesis
- plan appropriate client centred physical examination
what are the components of the physical exam?
- consent for PE gained
- further interpretation
- confirm an MSK problem
- determine impairments
- hypothesis
components of diagnosis?
- plan Rx
- develop treatment aims
- choose appropriate client centred Rx modalities
components of intervention
- client centred
- consent for treatment gained
- monitor client throughout
components of reassessment
- subjective and objective changes after each treatment modality
- outcome measurest
things that inform our CR?
- anatomy & biomechanics
- pathophysiology & MOI
- clinical interview and physical assessment
- individual patient context and risk factors
- EBP
what are the 3 main patterns of patient presentation in the shoulder?
Pain +/-
- weakness
- stiffness
- instability
may overlap with symptoms
what is a red flag?
symptoms suggestive of a serious pathology
what is a yellow flag?
psychological and social predictors of chronicity
what are some examples of a red flag?
Pain
- relentless, unremitting 20/10 VAS
- not responding to NSAID’s / Pain meds
- waking at night or unable to sleep
- no comfortable positions
- non mechanical in behaviour
Referred pain symptoms
- heart = tip left shoulder
- lungs = can refer pain to shoulder region & ovarian dysfunction
- Ca = Pancoast tumour (of the lungs)
History of recent surgery
medical history
- diabetes/ thyroid/ cancer
- steroid use – osteolysis, muscle ruptures
ICF - Functional Outcome Measures
SPADI - Shoulder Pain and Disability Index
ASES American Shoulder and Elbow surgeons
Simple Shoulder Test
DASH - Disabilities of the arm, shoulder, and hand
Pain Catastrophising Scale
IES - Impact of Events Scale
what is the patient specific functional scale ?
0-10 activity scoring capacity (level of difficulty)
what does the patient specific functional scale meausre?
with what functional activities are they having difficulty?
prognostic indicators for success of conservative treatment?
mild trauma, early presentation, acute onset, preceding unusual or heavy overuse injury as MOI
prognostic indicators that may indicate poor outcome?
time off work, severity of pain initially, prior episode, severe restriction ROM (abduction), C/Sp pain/ spondylosis/ radiculopathy, comorbidities
what are some other prognostic factors?
- risk factors
- medical co-morbidities
- outcome measures = very helpful in prognosis at outset of treatment
EBP
- anatomical differentiation
- there is a lack of specificity of the clinical tests
- radiological evidence of pathology not always same as clinical presentation/ diagnositc
- exercise programs
- conservative Mx vs surgery
what are the components of the risk profile development?
- area
- behaviour
- age & gender
- history
- function –> limitations
- medical history –> co-morbidities
- risk factors
–> smoking
–> alcohol
–> exercise history
–> sleep hygiene
–> co-morbidities
PAIN +/- STIFFNESS
where is the area of stiffness?
single / multi-joint movement
PAIN +/- STIFFNESS
wheat is the behaviour assessment?
24/24–> am/pm/ night
PAIN +/- STIFFNESS
history?
injury, insidious, idiopathic
PAIN +/- STIFFNESS
function
functional limitations – HBB, reaching OH, driving, hanging out wasing, ADL limitations
Pain & patient understnaidng – distress
PAIN +/- STIFFNESS
medical history
diabetes, arthritis, cancer Rx, family history, blood screens, hypermobility
PAIN +/- STIFFNESS
risk factors
lifestyle, exercise, medical, co-moridities
PAIN +/- INSTABILITY
behaviour?
24/24 - am/pm/night?
PAIN +/- INSTABILITY
history
injury, insidious, idiopathic
PAIN +/- INSTABILITY
area
single/ multi-jt movement
PAIN +/- INSTABILITY
functional limitations
feeling of slipping/ popping out, unstable, feel loose / out of place
PAIN +/- INSTABILITY
positional limitation
cocking position (stop sign), OH
PAIN +/- INSTABILITY
medical history
hypermobility, other joint laxity
PAIN +/- INSTABILITY
risk factors
sporting requirements , growth stages
PAIN +/- INSTABILITY
age
adolescents (18-40yo)
PAIN +/- WEAKNESS
area
single/multi jt movement
PAIN +/- WEAKNESS
behaviour
24/24
PAIN +/- WEAKNESS
history
acute trauma injury, insidious
PAIN +/- WEAKNESS
functional limitation
HBB, reaching OH, sleeping, lying on side
PAIN +/- WEAKNESS
medical history
arthritis, cancer Rx, family history, blood screens, RA/OA
PAIN +/- WEAKNESS
risk factors
lifestyle, smoking, obesity, poor exercise, medical co-morbs
what is symptom modification useful for?
to see if we can alter a patient’s symptoms in real time during the Ax
what does symptom modification do?
- guides our CR, hypothesis generation, potential Rx options and also give the patient feedback about symptpm reduction in functional movements which may motivate them, reassure them and help Rx buy in
what are the treatment priorities in MSK physio?
- therapeutic exercise prescription
- A&E
- manual therapy
EPA if required
other modalities if required
