Biomechanics
What are the motions at the sternoclavicular joint?
elevation/depression
protraction/retraction
axial rotation
What rotator cuff muscle does NOT insert on the greater tubercle?
subscapularis
What type of joint is the glenohumeral joint?
ball and socket
What is the roll and glide for glenohumeral abduction?
roll: superior
glide: inferior
Name the actions of each portion of the trapezius.
Upper: elevate scapula
Middle: adduct scapula
Lower: depress scapula
What are the two portions of the coracoclavicular ligament?
medial conoid and lateral trapezoid
Describe the term scapular rhythm
Motion of the scapula and humerus during shoulder movement. Occurs at a ratio of 2:1. 2 degrees of GH abduction to 1 degree of scapular upward rotation.
What is the origin and insertion of pectoralis major?
origin: medial half of clavicle and anterior surface of sternum, first 7 costal cartilages and aponeurosis of external oblique.
insertion: lateral lip of intertubercular sulcus of humerus.
What motion(s) does the superior GH ligament resist?
anterior translation of humeral head and ER at 0° abd
What are the motions that contribute to scapulothoracic elevation?
sternoclavicular elevation and acromioclavicular downward rotation
What is the action and innervation of teres major?
action: extension and IR
innervation: subscapular nerve
What is the structure and function of the disc at the sternoclavicular joint?
fibrocartilage
increases congruency b/w articulating surfaces and dissipates joint loads, helps to increase stability
What are the rotational adjustment motions that occur at the acromioclavicular joint?
Horizontal plane: IR/ER
Sagittal plane: anterior and posterior tilting
What is the origin, insertion, action, innervation and blood supply of teres minor?
origin: Lateral border of scapula
insertion: greater tubercle of humerus
action: external rotation and adduction
innervation: axillary nerve
blood supply: suprascapular artery, dorsal scapular artery
What is the convexity and concavity at the sternoclavicular joint?
Medial clavicle is concave horizontally and convex vertically.
Sternum is convex horizontally and concave vertically.