Upper extremity Flashcards
Functional articulations of the shoulder
Sterno-clavicular joint
Acromio-clavicular joint
Scapulo-thoracic joint
GH joint
Supra-humeral ‘sub-acromial’
Long head biceps and bicipital groove
Accessory movements
GH- distraction, compression AP glide, superior inferior glide
AC- distraction, compression, AP glide, superior inferior glide, rotation
SC- distraction, compression, AP glide, superior inferior glide, rotation
Scapulo-humeral rhythm
It facilitates the movements of the upper extremity by positioning the GH favourably
It prevents impingement between the scapula and the humerus
the first 30 degrees come specifically from the GH, after 30 degrees the movement moves in a 2:1 (GH:scap) meaning 120 degrees of the movement come from GH and 60 from scap
3 phases during arm abduction:
– phase 1:
—- Humerus- 30 degrees abduction
—- clavicle- 0-5 degrees elevation
—- scapula- minimal scapula movement medially
– phase 2:
—- humerus- 40 degrees abduction (up to 90 degrees)
—- scapula- 20 degrees lateral rotation
—- clavicle 15 degrees elevation
– phase 3:
—- humerus- 60 degrees abduction and 90 degrees lateral rotation
—- scapula- 30-40 degrees lateral rotation
—- clavicle- 30-50 posterior rotation and 15 degrees elevation
Roll of the clavicle
The only axial attachment for the entire upper extremity
The clavicle elevates, depresses, rotates, protracts and retracts. All movements are passive accessory movements.
All clavicular movements are essential to position the scapular in the optimal position to accept the head of the humerus
Essentially all movements of the GH joint involve some movement of the clavicle around the pivot point of the sternoclavicular joint
Role of the long and short head of the biceps in humeral head stability
Provides anterior stability to the GH, therefore failure of the stabilisation of the long head can have damaging effects on the GH and the rotator cuff function
Achieved through compression of the humeral head against the glenoid fossa
Observations that the tendon of the long head hypertrophies in patients with rotator cuff tears confirms that it has a role in GH stability
Short head:
– acts to ensure that the humerus stays away from the sub acromial space
Force coupling in the shoulder
Pivot-
Roll and slide at the shoulder
Maintains the joint congruity through range of movement
Convex- concave (opposite directions)
Humerus (convex, mover)
Scapular (stationary, concave)
Abduction:
– humerus- rolls superiorly from the pull of the supraspinatus
– scapular- slides inferiorly
Flexion/extension:
– the head of the humerus spins along with accompanying upwards rotation of the scapulothoracic joint. Assisted by rotation of the clavicle
Sub acromial space
Structures packed into the space:
– the tendon of the long head of the biceps muscle
– subacromial bursa
– rotator cuff (supraspinatus tendon)
Closing the gap:
– lifting the arm into abduction (due to the pull of the supraspinatus muscle will close the gap)
– lifting the arm in general
—- this can lead to shoulder impingement
Abnormal arthrokinematics:
– flat (17% of cases)
– curved (43%)
– hooked (39%)
—- about 70% of rotator cuff tears are associated with a hooked acromion
—- may be the result of the ossification of the coracoacromial ligament
– convex ‘upturned’ (1%)
Movers and stabilisers
Movers:
– deltoid
– supraspinatus
– biceps brachii
– brachioradialis
– pectoralis major
Joint stabilising tissues:
– capsule
– ligaments
– articular disc (AC and SC)
Stabilising muscles:
– subscapularis
– serratus anterior
– latissimus dorsi
—- when people have had an anterior dislocation, important to get the pt working on these muscles)
– coracobrachialis
– pectorals major
Differentiating different problems with the shoulder based on clinical presentation
Painful and weak:
– rotator cuff related shoulder pain
– subacromial- impingement syndrome
– SLAP lesion
Painful and stiff:
– adhesive capsulitis
– OA of GH or AC
Painful and unstable:
– dislocations
– repeated dislocations
