biol212 muscles that act on the arm (humerus) o.i.as

pectoralis major – origin

clavicle, sternum, and costal cartilages of upper ribs

pectoralis major – insertion

greater tubercle of humerus

pectoralis major – action

flexes, adducts, and medially rotates arm (GH joint)

latissimus dorsi – action

extends, adducts, and medially rotates arm (GH joint)

deltoid – origin

clavicle, acromion process, and spine of scapula

deltoid – insertion

deltoid tuberosity of humerus 

deltoid – action

abducts, flexes and extends, medially and laterally rotates arm (GH joint)

supraspinatus – origin

supraspinous fossa of scapula

supraspinatus – insertion

greater tubercle of humerus

supraspinatus – action

abducts arm and stabilizes glenohumeral joint
*Rotator cuff

infraspinatus – origin

infraspinous fossa of scapula

infraspinatus – insertion

greater tubercle of humerus

infraspinatus – action

laterally rotates arm and stabilizes glenohumeral joint
*Rotator cuff

subscapularis – origin

subscapular fossa of scapula

subscapularis – insertion

lesser tubercle of humerus

subscapularis – action

medially rotates arm and stabilizes glenohumeral joint
*Rotator cuff 

teres minor – origin

axillary border of scapula

teres minor – insertion

greater tubercle of humerus

teres minor – action

laterally rotates and adducts arm and stabilizes glenohumeral joint
*Rotator cuff

teres major – origin

inferior angle of scapula

teres major – insertion

intertubercular groove of humerus

teres major – action

adducts, extends, and medially rotates arm (GH joint)

coracobrachialis – origin

coracoid process of scapula

coracobrachialis – insertion

medial surface of humerus

coracobrachialis – action

flexes and adducts arm (GH joint)