shoulder OIAN

trapezius origin

superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of C7-T12, related supraspinous ligaments

trapezius insertion

superior border of spine of scapula, acromion, posterior border of lateral one-third of clavicle

trapezius action

superior fibers: elevate

middle fibers: retract scapula

inferior fibers: depress scapula, upward rotation

trapezius innervation

accessory nerve, CN XI

latissimus dorsi origin

spinous process of lower six thoracic vertebrae, through thoracolumbar fascia to spinous processes of lumbar vertebrae and related supraspinous ligaments; iliac crest, lower three-four ribs

latissimus dorsi insertion

intertubecular sulcus of humerus

latissimus dorsi action

extend, adduct, internal rotation of arm at shoulder joint

pulls trunk up, splints posterior abdomen

latissimus dorsi innervation

thoracodorsal nerve (C6, C7, C8)

levator scapulae origin

transverse processes of C1-C4

levator scapulae insertion

medial border of scapular from superior angle down to root of spine

levator scapulae action

elevates, downwardly rotates, retracts scapula

levator scapulae innervation

dorsal scapular nerve, C5

rhomboid minor origin

lower ligamentum nuchae, spinous processes of C7, T1

rhomboid minor insertion

medial border of scapula at root of the spine

rhomboid minor action

retracts and downwardly rotates scapula; assists with elevation of scapula

rhomboid minor innervation

dorsal scapular nerve, C5

rhomboid major origin

spinous processes of T2-T5 vertebrae and related supraspinous ligaments

rhomboid major insertion

medial border of the scapula from the root of the spine to the inferior angle

rhomboid major action

retracts and downwardly rotates scapula, assists with elevation of scapula

rhomboid major innervation

dorsal scapular nerve, C5

deltoid origin

inferior border of spine of scapula, acromion, anterior border of lateral one-third of clavicle

deltoid insertion

deltoid tuberosity of humerus

deltoid action

anterior fibers: flexion, internal rotation, horizontal adduction

middle fibers: abduction of arm past 15 degrees

posterior fibers: extension, external rotation, horizontal abduction of arm

deltoid innervation

axillary nerve (C5, C6)

supraspinatus origin

medial two-thirds of supraspinous fossa of scapula

supraspinatus insertion

greater tubercle of humerus, superior facet

supraspinatus action

initial 15 degrees of abduction of arm, holds head of humerus at glenohumeral joint

supraspinatus innervation

suprascapular nerve (C5, C6)

infraspinatus origin

medial two-thirds of infraspinous fossa of scapula

infraspinatus insertion

greater tubercle of humerus, middle facet

infraspinatus action

external rotation of arm at shoulder joint, holds head of humerus at glenohumeral joint

infraspinatus innervation

suprascapular nerve (C5, C6)

teres minor origin

upper two-hirds of posterior surface of lateral border of scapula

teres minor insertion

greater tubercle of humerus, inferior facet

teres minor action

external rotation, weak adduction of arm at shoulder joint, holds head of humerus at glenohumeral joint

teres minor innervation

axillary nerve (C5, C6)

teres major origin

facet on posterior surface of inferior angle of scapula; inferior one-third, posterior surface of lateral border of scapula

teres major insertion

medial lip of intertubercular sulcus of humerus

teres major action

internal rotation, adduction, and extension of arm at shoulder joint

teres major innervation

lower subscapular nerve (C5, C6)

triceps brachii long head origin

infraglenoid tubercle of scapula

triceps brachii long head insertion

olecranon process of humerus with tendons of medial and long heads

triceps brachii long head action

weak adduction and extension of arm at shoulder joint

triceps brachii long head innervation

radial nerve (C6, C7, C8)

pectoralis major origin

clavicular head - anterior/superior surface of medial half of clavicle; sternocostal head - lateral half of manubrium, sternum and costal cartilages of first seven ribs, aponeurosis of external oblique muscle

pectoralis major insertion

lateral lip of intertubercular sulcus

pectoralis major action

calvicular head - flexes an extended arm at shoulder joint

sternocostal head - extends a flexed arm at the shoulder joint

both - adduct, internal rotation, flexion, horizontal adduction of arm at shoulder joint

pectoralis major innervation

medial and lateral pectoral nerves (C5, C6, C7, C8, T1)

pectoralis minor origin

anterior surface and superior margin of ribs 3-5 near junction with costal cartilage, deep fascia of intercostal spaces

pectoralis minor insertion

medial border of coracoid process of scapula

pectoralis minor action

pulls scapula downward (depression), protraction, cups shoulder forward

pectoralis minor innervation

medial pectoral nerve (C8, T1)

subclavius origin

first rib at junction of costal cartilage

subclavius insertion

subclavian groove of clavicle

subclavius action

depresses clavicle (lateral/acromial end); stabilizes clavicle during shoulder joint movements

subclavius innervation

nerve to subclavius (C5, C6)

serratus anterior origin

outer surface and superior border of ribs 1-9 midway between angle and costal cartilages; fascia over related intercostal spaces; inferior part with external oblique muscle

serratus anterior insertion

costal surface of medial border of scapula

serratus anterior action

protracts and upwardly rotates scapula; holds scapula against thoracic wall; fixes scapula for other muscles

serratus anterior innervation

long thoracic nerve (C5, C6, C7)

subscapularis origin

medial two-thirds of subscapular fossa

subscapularis insertion

lesser tubercle of humerus

subscapularis action

internally rotates scapula; holds head of humerus in the glenohumeral joint

subscapularis innervation

upper and lower subscapular nerves (C5, C6)