SHOULDER Flashcards
What is the rotator cuff? What is it made up of? What is its main function? Injury leads to problems with which movement?
- 4 muscles surrounding glenohumeral joint
- Supraspinatous, infraspinatus, teres minor, subscapularis
- Draws humeral head into glenoid during ABduction: tendonitis and tears of rotator cuff will lead to problems with ABduction
What is this muscle? What is its function?
Supraspinatous: above spine of scapula
Initial abduction of arm (0 to 15°)
What is the most common rotator cuff muscle to be injured? Explain why
What type of athlete does this injury typically occur in?
Supraspinatous
→ tendon can become compressed between head of humerus and acromion process of scapula causing supraspinatous to become impinged in subacromial space ⇒ Tendinopathy or tear
Occurs in swimmers and throwers
How do you test for supraspinatous injury?
Empty can test
What is this muscle? What movements is it involved in?
Infraspinatus
External rotation and abduction of shoulder
What is this muscle? Which movements is involved in? What is its innervation?
Teres minor
External rotation and adduction of shoulder
Axillary nerve
What is this muscle? What movement is it involved in? By which nerves is it innervated?
Subscapularis
- Internal rotation of shoulder
- Innervated by subscapular nerves
Where do all of the nerves that innervate the rotator cuff come from?
Brachial plexus (nerves circled in red)
Which muscles are responsible for shoulder abduction? Give degrees
- Supraspinatous: first 15°
- Deltoid: primary shoulder abductor up to 90°
- Trapezius/serrated anterior: beyond 90°
What type of dislocation would cause sensory loss of deltoid and weak abduction of the shoulder? Explain why
Anterior shoulder dislocation
Commonly injures axillary nerve which runs below humeral head and wraps around neck
What are the three most common fractures in older adults?
- Hip
- Distal radius
- Proximal humerus
