What are the four joints that make up the shoulder complex?
- sternoclavicular (SC)
- acromioclavicular (AC)
- glenohumeral (GH)
- scapulothoracic (ST)
What motion does the sternoclavicular ligament restrict?
- limits accessory motion of the clavicular head
What motion does the interclavicular ligament restrict?
- prevents downward motion of the clavicle (proximal head moves upward)
Normal ROM values for the steernoclavicular joint
Elevation: 45 degrees
Depression: 10 degrees
Pro/retraction: 15 degrees
Rotation: 20-35 degrees (posterior only)
What direction is roll & slide in for pro/retraction at the sternoclavicular joint?
- roll & slide are in the same direction
What direction is roll & slide in during elevation & depression of the sternoclavicular joint?
- roll & slide are in opposite directions
What motion does the superior & inferior acromioclavicular ligament limit?
- prevents horizontal distraction
What motion does the coracoclavicular (trapezoid & conoid) ligament limit?
- limits upward scapula rotation
- transfers medially directed forces from glenoid (prevents medial displacement)
- prevents medial scapula displacement
- produces longitudinal clavicle rotation during upper extremity elevation
Normal ROM values of the acromioclavicular joint during scapular motion?
Upward rotation: 30 degrees
Anterior/posterior tilting: 5-30 degrees
Internal/external rotation: 5-30 degrees
What motion does the superior glenohumeral ligament limit?
- external rotation & inferior translation of humeral head
What motion does the middle glenohumeral ligament limit?
-prevents anterior displacement
What motion does the inferior glenohumeral ligament limit, anterior & posterior band?
Anterior band: limits external rotation
Posterior band: limits internal rotation
As a whole: limits abduction
What is the close packed position for the glenohumeral joint?
- 90 degrees abduction with full external rotation (throwing position)
Normal ROM values for the glenohumereal joint?
Flexion: 120 degrees & 60 degrees from rotation of the scapula
Internal rotation: 80 degrees (90 degrees if abducted)
External rotation: 60-65 degrees (90 degrees if abducted)
Abduction: 90 degrees (60 degrees if IR & 40 degrees if ER)
Extension: 60-70 degrees active & 80 degrees passive
What is scapulohumeral rhythm?
- glenohumeral joint & scapulothoracic joint have a 2:1 ratio
When is shoulder abduction mostly related to sternoclavicular joint & acromioclavicular joint?
- Sternoclavicular joint is responsible for the majority of motion up to 90 degrees abduction
- Acromioclavicular joint is responsible for the majority of motion past 90 degrees abduction
How much does the clavicle retract during full abduction?
- 15 degrees beyond resting position
What happens to the scapula when it goes through full abduction?
- medial border & inferior angle goes inward
- lateral border externally rotates away from the ribcage
What ligament is the primary contributor to clavicular rotation?
- coracoclavicular ligament
Normal ROM value for clavicular rotation
20-25 degrees posteriorly
Why is humeral external rotation important?
- to get the tubercle out of the way to have enough space to complete the motion, same thing happens during shoulder flexion
How much shoulder flexion & extension occur during gait?
Flexion: 25 degrees
Extension: 10 degrees
What muscles are involved in scapula elevation?
- levator scapula
- rhomboid minor
- rhomboid major
- upper trapezius
What muscles are involved in scapula depression?
- lower trapezius
- latissimus dorsi
