Shoulder

Shoulder

1. Alex's Hx check list

2. Examinations of the shoulder to narrow down the source of the issue

   • Observation
   • Palpation (ST and Bony)
     • SITs - rotator cuff muscles of the shoulder
     • important ligaments between bony structures
       • 1. (AC) acromioclavicular
       • 2. (CA) coracoacromial
       • 4. (GH) glenohumeral
         • Glenohumeral ligaments are important stabilizers at extremes of motion by tightening, thereby helping reduce joint reactive forces (shoulders may test lax but be completely stabled due to primary stabilizers)
           • When motion or forces (macro or micro) overwhelm or alter these constraints centration is lost resulting in subluxation, dislocation or functional instability.
       • 3. (CC) coracoclavicular
     • important tendons - muscle to bone
       • bicipetal tendon
         • The tendon of long head of biceps enters the joint space through the bicipital groove and lies in a tubular synovial sheath as it passes posteriorly and medially across the superior aspect of humeral head.
       • SITS tendons - particularly supraspinatus
     • Primary stabilsers of the humeral head
       • Dynamic ligaments, by virtue of the blending of their tendons with the GH capsule and ligaments, selective contraction of the cuff muscles can adjust the tension in these structures (GH capsule and ligaments) producing dynamic ligaments
     • By contracting together, the rotator cuff muscles and the biceps press the humeral head into the glenoid fossa, locking it into position and thus providing stability
       • By contracting selectively, the rotator cuff can resist displacement forces resulting from contraction of the shoulder prime movers
     • secondary stabilisers
       • important at end ROM
   • ROM (active and passive)
   • Joint challenge
     • There are 5 functional shoulder joints
       • 1. (SC) - sternoclavicular 2. (AC) - acromioclavicular 3. (SA) suprahumeral articulation 4. (GH) - glenohumeral 5. (ST) - scapulothoracic functional joint
         • 5. ST - It is formed between the anterior scapula and the posterior thoracic rib cage (ribs 2-7) The scapula's attachment to the axial skeleton is purely musculotendinous, formed by the trapezius and serratus muscles
           • Disease mechanism: Fibrous adhesions can occur following a shoulder injury, particularly if the joint has been immobilized for a long period of time. This severely impairs the movement of the shoulder, particularly with abduction past 90°
         • 4. GH stability - in normal motion the head of the humeral stays relavively central and with abduction the head naturally deviates 6mm at the extremes of the motion
           • Disease mechanism - an unstable GH joint will display excessive excurion on the joint and the humeral head will deviate 10mm+
           • Normal Posterior translation - In horizontal abduction with lateral rotation, the humeral head deviates posteriorly 4mm thereby reducing stress on the anterior shoulder stabilizers.
           • GH instability - posterior translation lost
         • SC - The fibrous capsule surrounds the articular surfaces, thickened in front and behind but thin superiorly and inferiorly.
           • SC joint does not commonly degenerate and only accounts for 1% of all joint dislocations
           • check for normal ROM - pt lifts arm up and down (flex/extend)
         • AC disease mechanism: A wedge-shaped articular disc is found in the AC joint, partially separating the joint surfaces commonly show degeneration with age
           • shows marked degeneration by the 4th decade. By the 6th decade AC joint degeneration is common.
         • 3. Glenoid joint mainly stabilized by joint capsule, and negative joint pressure, and the glenoid labrum contributes 10-20% of the stabilization forces
         • GH+ ST combined movement = scapulohumeral rhythm
           • Resistance and muscle fatigue decreases the scapulohumeral rhythm resulting in increased scapulothoracic contribution
           • reports reduced scapulohumeral rhythm in patients with rotator cuff tears
           • Any alteration of the scapulohumeral rhythm may affect the centralizing force of the rotator cuff muscle resulting in a reduction of the subacromial space
           • Reduced glenoid rotation effect the contractile strength of the deltoid muscle
   • Special tests

3. Pathological conditions of the shoulder

   • Extrinsic shoulder px
     • Visceral cause
       • Cardiovascular lesions
       • Pleural/ pulmonary/ mediastinal lesions
       • Gastric and duodenal disorders
       • Liver and gall bladder disorders
       • Pancreatic disease
     • Somatic causes
       • Cervicogenic disorders
         • nerve root
         • poster Facet syndrome
         • CNS involvement
       • Thoracogenic disorders
         • thoracic outlet syndrome
         • interscapular pain
         • T4 syndrome
         • MF Trigger Points
       • Shoulder-hand syndrome (reflex sympathetic dystrophy)
   • intrinsic shoulder px
     • Subacromial impingement syndroms
     • Stage 1 - oedema + haemorrhage
       • Stage 2 - cuff fibrosis and partial tear
         • stage 3 - full thickness tear
     • Adhesive capsulitis/ frozen shoulder

4. Important Anatomy to consider

   • Labrum
     • The glenoid cavity is deepened by the glenoid labrum, a ring of fibrocartilage attached to the boundaries of glenoid fossa. The articular area of glenoid and labrum is less than a third of the area of humeral head. Articular surfaces are lined by hyaline cartilage. Over the humeral head this is thicker in the middle and thinner towards the periphery.
   • The non-articular surfaces of the joint are lined with synovial membrane, which communicates with the subscapular bursa.

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