Rotator Cuff

Rotator Cuff

1. Supraspinatus

   • origin: supraspinous fossa
   • insertion: greater tubercle of the humerus
     • superior facet
   • innervated by the suprascapular nerve
   • lateral rotation an abduction of the arm
     • cannot complete abduction but can hold the arm in an elevated position
   • suprascapular and dorsal scapular arteries

2. Infraspinatus

   • origin: infraspinatus fossa
   • insertion: greater tuberosity/tubercle of the humerus
   • innervated by suprascapular nerve
   • suprascapular and circumflex arteries
   • lateral rotation of the arm

3. Teres minor

   • origin: lateral border of the scapula
   • insertion: greater tuberosity of the humerus
   • innervated by the axillary nerve
   • circumflex scapular artery
   • lateral rotation of the arm and weak adductor of the humerous
   • holds the head of the humerus down against the upward movement of the deltoid muscle during abduction

4. Subscapularis

   • origin: subscapular fossa
   • insertion: lesser tuberosity of the humerus
   • innervated by the upper and lower sub scapular nerves (C5-6)
   • allows for medial rotation of the arm
   • subscapular artery

5. Injuries

   • rotator cuff disease is the most common cause of shoulder pain
   • supraspinatus tendon is particularly vulnerable to degenerative damage
   • dull ache deep in the shoulder, disturbed sleep and loss in range of motion
   • external tests
     • external rotation test
       • arms by sides at 90 degrees
       • patient should attempt to externally rotate against resistance
       • weakness suggests infraspinatus or teres minor tears
     • lift-off test
       • hands at back, just above buttocks
       • patient should attempt to lift hands off back against resistance
       • weakness suggests subscapularis tear
     • forward elevation test
       • patient should try to elevate their arms as high as possible against resistance
       • weakness suggests tear in supraspinatus
     • impingement is another test that can be done
   • treatments
     • physiotherapy
     • ice
     • surgery
     • corticosteroid injections
     • NSAIDs