PT3 - The Shoulder Complex And Orientating The Hand Flashcards
What are the functions of the shoulder?
- shoulder girdle => orientation of hand to any position
- CNS may sacrifice anatomical structure of shoulder to maintain hand dexterity
- upper limb has more mobility, but at the cost of structural stability
What are the articulations of the shoulder?
- stenoclavicular
- acromioclavicular
- scapulothoracic
- glenohumeral (ball and socket)
- supra-humeral (sub-acromial)
- long head of biceps and Bicipital groove
Describe the structure of the SC joint
- shallow, saddle shaped between manubrium and first costal cartilage
- sternal articular surface larger than sternum
- convex vertically + concave in sagittal plane
- lined with fibrocartilage + fibrocartilaginous disc => divides joint into 2 synovial cavities (each lined with it’s own membrane)
- fibrous capsule surrounds articular surfaces, thicken in front + behind but thin above and below
Name the ligaments around the AC joint
From medial to lateral:
- conoid ligament = clavicle => scapula
- trapezoid ligament = clavicle => scapula
- acromioclavicular ligament = clavicle => acromion
- coracoacromial ligament = scapula => acromion
How many bones meet at the AC joint?
- 2 bones = clavicle + scapula via acromion
What are the movements available at the AC joint?
- plane synovial joint => gliding movements
What happens when you get to the end of range of AC joint moment?
- AC becomes part of complex movement = global movement of shoulder complex
How can this joint be injured?
- FOOSH
- landing direction on acromion
- disruption of ligamentus support
How can you assess for AC injury?
- graded based on the number of ligaments disrupted
- might notice a step between clavicle and acromion
- might notice laxity in ligament
- common site of osteoarthritis
- end ranges of movement causes compression and degenerative changes
What is the structure of the AC joint?
- planar synovial joint
- located between oval facet at lateral end of clavicle + facet at medial aspect of acromion
- articular surfaces lined with fibrocartilage
- wedged-shaped articular disc separates joint surfaces
- capsule is attached to articular margins + reinforced superior and inferior to AC ligaments
- coracoclavicular ligament (+conoid + trapezoid components) => major stability of joint
What is the functional anatomy of the rotator cuff?
- dynamic stability of GH joint (unlike passive stability of ligaments in AC)
- maintaining integrity of glenoid in capsule
- combines with joint capsule
- less reliant on passive structures to support the shoulder
- RCM sometimes described as dynamic ligaments
What are the muscles of the RC?
- teres minor
- infraspinatus
- supraspinatus
- subscapularis
What is the functional anatomy of the rotator cuff?
- RC does not permit assessment of individual musculotendinous unit => think of them as a whole structure
- tendons fuse into 1 structure
- supraspinatus + infraspinatus fuse at insertion (greater tubercle of humerus)
- teres minor + infraspinatus fuse proximally to musculotendonous junction
- subscapularis + supraspinatus tendons fuse => sheath around bicep tendon
- RC tendons adhere to GH joint capsule
What is the function of the RC?
- dynamic stability of huméral head in glenoid fossa
- blend with joint capsule => layers of fibres in different directions
- high muscle spindle control => act as ligaments
- support inferior glide of humeral head during abduction to maintain stable contact with glenoid (think patella in knee)
What is the function of the long head of the bicep?
- attaches to scapula
- humerus glides along bicep => facilitates downward shift of humeral head
- bicep assists RC dynamic stabilisation
- triceps similar, but not as much involvement as biceps
What is impingement syndrome?
- as arm elevates, if no control of GH => compress structures within subacromial space
What is the function of the long head of bicep?
- neither head attaches to humerus
- antagonistic action on passive humerus (allows humerus to slide along LHB tendon)
- LHB alters axis for G/H motion during abduction
What are the functions of the scapulothoracic joint?
- serratus anterior provides separation for 2 sides of scapulothoracic articulation
- inter-serratus-thoracic ‘articulation’ => outside of thorax + ribs + medial surface of serratus anterior + loose fatty tissue allowing gliding
- inter-thoracic scapular ‘articulation’ between lateral surface of serratus anterior + anterior surface of subscapularis
What muscles attach to the scapulothoracic joint?
- latissimus dorsi
- trapezius
- rhomboid minor + major
- pec minor + major
- omohyoid
- levator scapulae
- serratus anterior
What symptoms can you have at the shoulder?
- painful/weak e.g. rotator cuff related shoulder pain
- painful/stiff e.g. adhesive capsulitis & OA
- painful and unstable e.g. dislocation
What diagnosis may you have for RC related shoulder pain for: Painful + Weak
- subacromial pain (impingement) syndrome
- rotator cuff tendinopathy
- symptomatic partial or full rotator cuff tears
- tends to be pain on activity
Where might you experience RC pain?
- 45 - 120 degrees => RC are working hard to keep shoulder away from body
Where in the pain arc might you see acromioclavicular pain?
- 170-180 degrees (top of arc)
Which muscle injury in the shoulder is less common?
- deltoid
- stress + mechanical force are less robust
- if you have a deltoid injury => you’ll have a mechanical shoulder injury
Which muscles work together to maintain the health of the GH movement?
- RC muscles
- RC partial + full thickness tears can result in reduced synergy at shoulder
What diagnosis may you have for RC related shoulder pain for: Painful + Stiff
- adhesive capsulitis (frozen shoulder)
What are the signs + symptoms of adhesive capsulitis/frozen shoulder?
- poorly understood
- involves substantial pain
- thickening of joint capsule
- capsule restricts all ranges of movements
- pathological process involves body forming excessive scar tissue or adhesions across GH joint
- can occur spontaneously (primary/idiopathic adhesive capsulitis) or following shoulder surgery/trauma (secondary adhesive capsulitis)
- incidence is higher in diabetic patients
- self-limiting disease, resolves in 1-3 years, however may have long-lasting symptoms
What is the primary complaint of patients with adhesive capsulitis?
- loss of range of movement
What is the key differential way of testing adhesive capsulitis?
- active + passive capsular movement will be the same
- strange end feel => physically the capsule is restricting the range
What are painful and unstable shoulder symptoms associated with?
- dislocation
How does dislocation usually occur?
- abduction or external rotation injuries
- trauma catches the protective muscles unprepared or overwhelms them
- usually anterior, due to strength of supporting structures
- in the young anterior g-h ligaments give
- in elderly posterior supports (RC) tear => humeral head rolls over anterior rim
- capsule and GH ligaments remain intact
When do osteopaths usually treat dislocations of the GH?
- post healing
- patient may have a history of dislocation
- don’t usually see patients on first day
What tissues are involved in dislocation of the humerus?
- anterior + inferior dislocation
- posterior RC remain intact
- ligaments in the front of shoulder are disrupted
- may also involve labrum + SLAP
What is a SLAP lesion?
- Superior Labrum Anterior Posterior
- where the long head of the bicep attaches into the labrum can tear
- superior part of labrum, both anteriorly and posteriorly
How do dislocations in the elderly differ from the young?
- young = anterior + inferior
- elderly = posteriorly + inferiorly (slides off back of glenoid because RC isn’t as strong posteriorly)
PT Vignette:
PT is a swimmer and osteopath (from a young age) and presents with tachycardia post SC dislocation (after osteopathic examination). They practised with men at a young age as their arms were always weaker.
Why might the PT’s tachycardia be related to their SC dislocation?
What might assist the PT to adapt to their environment?
What options are available for referral?
What contributing factors might have lead to the PTs SC dislocation?
- sinus for heart rhythm is due to the baroreceptor for the heart residing under the clavicle (aortic arch + carotid sinus)
- PT should strengthen their relegation ship between their humerus => clavicle => scapula => thoracic spine e.g. windsurfing in isometric holds to strengthen posterior chain, offsetting anterior chain movement during osteopathy practise
- Physiotherapy or surgery
- Swimmer from a young age, strengthening using endurance training rather than weight training loading slowly, osteopathy is a anterior body focus, reduced MM endurance of posterior MM to assist
What can happen to AC injuries that have been pinned?
- PT does not have any movement in shoulder
- Pins can travel to other areas of the body e.g. PT had AC pin that moved to wrist (was getting wrist pain), surgeon removed pin, but didn’t put pin back in AC as AC didn’t have any pain
