ES 553- shoulder muscles (AOIN)

deltoid

trapezius

latissimus dorsi

teres major

infraspinatus

subscapularis

supraspinatus

teres minor

rhomboid major and minor

levator scapula

serratus anterior

pectoralis major

pectoralis minor

subclavius

biceps brachii

triceps brachii

coracobrachialis

deltoid origin and insertion

O: lateral 1/3 of scapula, acromion, spine of scapula

I: deltoid tuberosity

trapezius origin and insertion

O: external occipital protuberance, medial portion of superior nuchal line of the occiput, ligamentum nuchae, spinous processes of C7-T12

I: lateral 1/3 of clavicle, acromion, spine of scapula

latissimus dorsi origin and insertion

O: inferior angle of scapula, spinous processes of last 6 thoracic vertebrae, last 3 or 4 ribs, thoracolumbar aponeurosis, posterior iliac crest

I: intertubercular groove of humerus

teres major origin and insertion

O: inferior angle and lower 1/3 of lateral border of the scapula

I: crest of the lesser tubercle of the humerus

infraspinatus origin and insertion

O: infraspinous fossa of the scapula

I: greater tubercle of the humerus

subscapularis origin and insertion

O: subscapular fossa of the scapula

I: lesser tubercle of the humerus

supraspinatus origin and insertion

O: supraspinous fossa of the scapula

I: greater tubercle of the humerus

teres minor origin and insertion

O: upper 2/3 of lateral border of the scapula

I: greater tubercle of the humerus

rhomboid major and minor origin and insertion

major- O: spinous processes of T2-T5

I: medial border of the scapula between the spine of the scapula and inferior angle

minor- O: spinous processes of C7-T1

I: upper portion of medial border of the scapula, across from spine of the scapula

levator scapula origin and insertion

O: transverse processes of 1st-4th cervical vertebrae

I: medial border of scapula, between superior angle and superior portion of spine of scapula

serratus anterior origin and insertion

O: external surfaces of upper 8 or 9 ribs

I: anterior surface of medial border of the scapula

pectoralis major origin and insertion

O: medial half of clavicle, sternum, and cartilage of 1st-6th ribs

I: crest of greater tubercle of humerus

pectoralis minor origin and insertion

O: 3rd, 4th, and 5th ribs

I: medial surface of coracoid process of the scapula

subclavius origin and insertion

O: first rib and cartilage

I: inferior surface of middle 1/3 of clavicle

biceps brachii origin and insertion

long head- O: supraglenoid tubercle of scapula

short head- O: coracoid process of scapula

I: tuberosity of the radius, aponeurosis of the biceps brachii

triceps brachii origin and insertion

long head- O: infraglenoid tubercle of the scapula

lateral head- O: posterior surface of proximal half of the humerus

medial head- O: posterior surface of distal half of the humerus

I: olecranon fossa of the ulna

coracobrachialis origin and insertion

O: coracoid process of the scapula

I: medial surface of the mid-humeral shaft

deltoid action

all fibers- abduct the shoulder (glenohumeral joint)

anterior fibers- flex the shoulder, medially rotate the shoulder, horizontally adduct the shoulder

posterior fibers- extend the shoulder, laterally rotate the shoulder, horizontally abduct the shoulder

trapezius action

upper fibers (bilaterally)- extend the head and neck

upper fibers (unilaterally)- laterally flex the head and neck to the same side, rotate the head and neck to the opposite side, elevate the scapula (scapulothoracic joint), upwardly rotate the scapula

middle fibers- adduct the scapula, stabilize the scapula

lower fibers- depress the scapula, upwardly rotate the scapula

latissimus dorsi action

-extend the shoulder (glenohumeral joint)

-adduct the shoulder

-medially rotate the shoulder

teres major action

-extend the shoulder (glenohumeral joint)

-adduct the shoulder

-medially rotate the shoulder

infraspinatus action

-laterally rotate the shoulder (glenohumeral joint)

-adduct the shoulder

-stabilize the head of the humerus in the glenoid cavity

subscapularis action

-medially rotate the shoulder (glenohumeral joint)

-stabilize the head of the humerus in the glenoid cavity

supraspinatus action

-abduct the shoulder (glenohumeral joint)

-stabilize the head of the humerus in the glenoid cavity

teres minor action

-laterally rotate the shoulder (glenohumeral joint)

-adduct the shoulder

-stabilize the head of the humerus in the glenoid cavity

rhomboid major and minor action

-adduct the scapula (scapulothoracic joint)

-elevate the scapula

-downwardly rotate the scapula

levator scapula action

unilaterally- elevate the scapula (scapulothoracic joint), downwardly rotate the scapula, laterally flex the head and neck, rotate the head and neck to the same side

bilaterally- extend the head and neck

serratus anterior action

with the origin fixed- abduct the scapula, upwardly rotate the depress the scapula, hold the medial border of the scapula against the rib cage

with the scapula fixed- may act to elevate the thorax during forced inhalation

pectoralis major action

all fibers- adduct the shoulder, medially rotate the shoulder, assist to elevate the thorax during forced inhalation (with the arm fixed)

upper fibers- flex the shoulder, horizontally adduct the shoulder

lower fibers- extend the shoulder

pectoralis minor action

-depress the scapula

-abduct the scapula

-downwardly rotate the scapula

with the scapula fixed- assist to elevate the scapula during forced inhalation

subclavius action

-depress the clavicle and draw it anteriorly

-elevate the first rib (to assist during inhalation)

-stabilize the sternoclavicular joint

biceps brachii action

-flex the elbow (humeroulnar joint)

-supinate the forearm (radioulnar joint)

-flex the shoulder (glenohumeral joint)

triceps brachii action

all heads- extend the elbow (humeroulnar joint)

long head- extend the shoulder (glenohumeral joint), adduct the shoulder

coracobrachialis action

-flex the shoulder (glenohumeral joint)

-adduct the shoulder

deltoid nerve innervation

axillary n.

trapezius nerve innervation

-spinal portion of cranial nerve XI (accessory)

-ventral ramus

latissimus dorsi nerve innervation

thoracolumbar n.

teres major nerve innervation

lower subscapular n.

infraspinatus nerve innervation

suprascapular n.

subscapularis nerve innervation

upper and lower subscapular n.

supraspinatus nerve innervation

suprascapular n.

teres minor nerve innervation

axillary n.

rhomboid major and minor nerve innervation

dorsal scapular n.

levator scapula nerve innervation

-C3

-C4

-dorsal scapular n.

serratus anterior nerve innervation

long thoracic n.

pectoralis major nerve innervation

upper fibers- lateral pectoral n.

lower fibers- lateral and medial pectoral n.

pectoralis minor nerve innervation

medial pectoral n.

*with fibers from a communicating branch of the lateral pectoral n.

subclavius nerve innervation

subclavian n.

biceps brachii nerve innervation

musculocutaneous n.

triceps brachii nerve innervation

radial n.

coracobrachialis nerve innervation

musculocutaneous n.