MA I: Shoulder Flashcards
MA I: Shoulder
The clavicle surface in the sternoclavicular joint is _____ along its longitudinal diameter, and ______ along its transverse diameter
convex, concave
MA I: Shoulder
kinematics of the sternoclavicular joint:
- Elevation 45 deg; depression 10 deg (roll and slide in opposite directions)
- Protraction up to 30 deg; retraction up to 30 deg (roll and slide in similar directions)
- Axial rotation up to 35 deg from neutral (spin)
MA I: Shoulder
What type of synovial joint is the acromioclavicular joint?
plane joint
MA I: Shoulder
acromioclavicular joint: upward and downward rotation
summation of clavicular elevation at the SC joint and scapular upward rotation at the AC joint
MA I: Shoulder
elevation and depression of the scapulothoracic joint
elevation at the sternoclavicular joint and downward rotation at the acromioclavicular joint
MA I: Shoulder
kinematics of protraction and retraction
protraction at the sternoclavicular joint and slight internal rotation at the acromioclavicular joint
MA I: Shoulder
Average “resting” posture of the scapula
- 10° anterior tilt
- 5-10° upward rotation
- 35° internal rotation (plane of scapula)
MA I: Shoulder
at the end range of full shoulder abduction, the position of the scapula is…
posteriorly tilts 20 deg and externally rotates 10 deg
- Clavicle retracts at sternoclavicular joint, which coupled with external rotation of scapula on thorax
- Acromioclavicular joint rotates internally at the same time which offsets a large portion of the scapulothoracic external rotation that occurs from the sternoclavicular joint retraction
MA I: Shoulder
what is the angle of retroversion of the humerus
30 deg
MA I: Shoulder
Scapulohumeral rhythm
- 120 deg GHJ
- 60 deg STJ:
- 30° elevation SCJ
- 30° upward rotation at the ACJ
- From 0-90 mostly SCJ
- From 90 to 180 mostly ACJ
MA I: Shoulder
elevators of the scapulothoracic joint:
- Upper trapezius
- Levator scapulae
- Rhomboid major/minor
MA I: Shoulder
depressors of the scapulothoracic joint
- Lower trapezius
- Latissimus dorsi
- Pectoralis minor
- Subclavius
MA I: Shoulder
protractors of the scapulothoracic joint:
serratus anterior
MA I: Shoulder
retractors of the scapulothoracic joint:
- Middle trapezius
- Lower trapezius
- Rhomboid minor
- Rhomboid major
MA I: Shoulder
The prime muscles that abduct the GH joint are the
anterior deltoid, middle deltoid, and supraspinatus