upper extremity Flashcards
functional articulations of shoulder
shoulder girdle increases ROM with less compromise of stability
sterno-clavicular joint (saddle synovial)
acromio-clavicular joint (synovial plane)
scapula- thoracic joint (false joint)
gleno-humeral joint (ball & socket)
supra-humeral joint (sub-acromial)
accessory movements of shoulder
GH: distraction, compression, AP glide, sup/ inf glide
AC: distraction, compression, AP glide, sup/ inf glide, rotation
SC: distraction, compression, AP glide, sup/ inf glide, rotation
scapulo-humeral rhythm
=the timing of movement at these joints (Gh & ST) during shoulder elevation
permits largets ROM of any complex in body
shoulder girdle increases ROM with less compromise of stability (4 joints vs 1 joint)
phase 1–> 30 degree humeral abduction. 0-5 degree clavicle elevation/ minimal medial scap movement
phase 2–> 40 degree humeral abduction. 20 degree lateral rotation scap. 30-50 degrees post rotation clavicle & 15 degree elevation
phase 3–> 60 degree humeral abduction & 90 degree lateral rotation. 30-40 degree lateral rotation scapula. 30-50 degrees post rot clavicle & 15 degree elevation
force coupling around pivot point
2 opposing forces rotating around a pivot point. There are multiple forces at any given moment. These can be equal or unequal, depending on the function required and balance of moving elements such as muscles and balance of stabilising elements such as ligaments.
role of short & long head of biceps in humeral stability
Provides anterior stability to the GH, therefore failure of the stabilisation of the LHB can have damaging effects on GH and Rotator Cuff (RC) function
Achieved through compression of the humeral head against the glenoid fossa
Observations that the tendon of LHB hypertrophies in patients with RC tears confirms that it has a role in GH stability
the long head pulls the arm away from the trunk (abduction) and turns it inwards (inward rotation) whereas the short head pulls the arm back towards the trunk (adduction).
roll & slide principles in shoulder
Maintains joint congruity through range of movement
GH is an example of convex on concave; where the moving bone (humerus) is convex and the stationary bone (scapular) is concave.
The humerus superior rolls, whilst scapular slides inferiorly during abduction.
During flexion/extension, the head of the humerus spins along with accompanying upward rotation of the scapulothoracic joint. Assisted by rotation of the clavicle.
role of clavicle
The clavicle is 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 glenohumeral joint involve some movement of the clavicle around the pivot point of the sternoclavicular joint.
movers vs stabilisers
Movers–> deltoid, supraspinatus, biceps brachii, brachioradialis, pectoralis major
Joint stabilising tissues–> capsule, ligaments (coracoacromial, coracohumeral, glenohumeral ligaments), articular disc (AC/ SC joints)
Stabilising muscles–> subscapularis, serratus anterior, latissimus, coracobrachialis, pectoralis minor
role of subacromial space
inside the space is the rotator cuff tendons, the long head of biceps tendon, and the coraco-acromial ligament, all surrounded by the subacromial bursa which helps to reduce friction between these structures.
painful and weak pathologies
-Rotator cuff related shoulder pain
-Subacromial impingement syndrome
-SLAP lesion
painful and stiff pathologies
-Adhesive capsulitis
-Osteoarthritis (bony remodelling) of GH and AC
painful and unstable pathologies
Dislocations/ repeated dislocations
flexion torque in pronation/ supination
Flexion torques are 70% greater than extension torque. The torque force needed for a bicep curl is 70% greater than an extension push down.
Flexion torque with supination are 20% greater than with pronation.
Brachioradialis in the mid prone (bowstringing) increases the power of flexion
elbow- 3rd class lever
Lever= A lever system is made up of three parts, an effort, a load, and a fulcrum. In the human body, the effort is provided by the muscle (the muscles point of application/insertion), the load is the weight of the body and any additional resistance, and the fulcrum is the joint itself.
The Elbow is an example of a 3rd class lever during flexion
elbow roll and slide
-The Ulnar is the concave surface
-The Humerus is the convex surface.
-The humerus is passive in both flexion and extension, which is driven by active movement of the ulnar and radius.
-On elbow flexion the roll and slide move in the same direction.
