Shoulder Girdle Flashcards
What is the main purpose of the shoulder girdle?
• To increase the movement of the GH joint
What is the scapular plane? Why is it significant?
- About 30 degrees from the horizontal
* Because most shoulder movements occur in this plane
What are the 3 joints within the shoulder girdle? Which is not a true joint and why?
- Sternoclavicular joint
- Acromioclavicular joint
- Scapulothoracic joint
- Scapulothoracic joint isn’t a true joint because it’s not fibrous, synovial or cartilaginous; muscle is opposing muscle (serratus anterior and subscapularis)
What are the articulations of the sternoclavicular joint? What type of joint is it and what does that mean it contains? What type of structure is the joint and what movement does that give it?
- Head of clavicle articulates w/ the clavicular notch in the manubrium
- Synovial joint: fibrous capsule, synovial membrane, articular cartilage, fibrocartilage pad (sternoclavicular disk to improve bone congruency and increase SA to reduce compressional stress- unique b/c attaches to both bones and prevents superior translation)
- Ball-and-socket joint: triplanar movement
List the ligaments supporting the sternoclavicular joint, what type of ligament they are, where they run from, and what movements they prevent. Why do all ligaments prevent superior translation?
- Anterior and posterior sternoclavicular ligaments; capsular ligament that runs from clavicular head to manubrium; prevents anterior and posterior translation of the clavicular head
- Interclavicular ligament; capsular ligament that runs from one clavicular head to superior manubrium to the other clavicular head; prevents lateral translation
- Costoclavicular ligament; extrinsic ligament that runs from underside of clavicular neck to 1st rib; prevents medial and superior translation
- Typically we are hit clavicle from lateral side and so pushed medially & superiorly
What are the articulations of the acromioclavicular joint? What type of joint is it? What type of structure is the joint and what movement does that give it?
- Acromium articulates with the acromial head of clavicle
- Synovial joint
- Planar joint- one surface sliding on another and allows scapula to move somewhat independently of clavicle
List the ligaments supporting the acromioclavicular joint, what type of ligament they are, where they run from, and what movements they prevent.
- Superior and inferior acromioclavicular ligaments; capsular ligaments that run from acromium to acromial head of clavicle; prevent…
- Coracoclavicular ligament (formed of 2 bundles- trapezoid/conoid lig’t); extrinsic ligaments that run from coracoid process to clavicle; prevents superior translation of clavicle
What is the difference between shoulder separation and shoulder dislocation?
- Shoulder separation discusses acromioclavicular joint
* Shoulder dislocation discusses GH joint
If you have limited scapular movement, how would you compensate?
• Use extreme ROM of GH joint
What joint does shoulder movement primarily happen (aka, axis of rotation)? What are the 4 main motions at the shoulder girdle (2 at frontal, 1 at transverse, 1 at sagittal)?
- Sternoclavicular joint
- Elevation/depression
- Protraction/retraction- rotation away/toward vertebral column
- Upward/downward rotation – inferior angle rotates up/out or down/in
- Anterior/posterior tilt of scapula- inferior angle moves away from thorax for anterior tilt
How much movement occurs at the GH joint compared to sternoclavicular joint when humerus moves?
• 2x the amount of movement at GH joint than at the sternoclavicular joint
What is a force couple?
• 2+ muscles pull in different directions to achieve a single movement, like upward/downward rotation
What is the difference between the right and left sides of the UE blood supply?
- R: aortic arch to brachiocephalic trunk to subclavian (brachium supplied) and common carotid (brain)
- L: aortic arch to subclavian and common carotid
What does brachium and antebrachium mean?
- Brachium is from the shoulder to elbow
* Antebrachium is the elbow to wrist
