Anatomical Foundations: Shoulder (actions, origins, insertions, innervations)

pectoralis major

pectoralis major origin

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

pectoralis major insertion

crest of greater tubercle of humerus

pectoralis major action

flexes, adducts, and medially rotates arm (inward)

subclavius

subclavius action

depress and anteriorly draw clavicle, elevate first rib, stabilize, sternoclavicular joint

subclavius origin

first rib cartilage

subclavius insertion

inferior surface of middle third of clavicle

pectoralis major innervation

lateral and medial pectoral nerves (C5-T1)

subclavius innervation

subclavian nerve (C5, C6)

pectoralis minor

pectoralis minor origin

ribs 3-5

pectoralis minor insertion

coracoid process of scapula

pectoralis minor action

elevates ribs, draws scapula down and medially

pectoralis minor innervation

medial pectoral nerve (C8-T1)

deltoid

deltoid origin

lateral third of clavicle (anterior), acromion (middle), and spine of scapula (posterior)

deltoid insertion

deltoid tuberosity (lateral side of the body of the humerus)

deltoid action

-all fibers: abduct shoulder (GHjoint)

-anterior: flex, internally (medially) rotate, and horizontally adduct shoulder (GH joint)

-posterior: extend, externally (laterally) rotate, and horizontally abduct shoulder (GH joint)

deltoid innervation

axillary nerve (C5, C6)

latissimus dorsi

latissimus dorsi origin

inferior angle of scapula, spinous process of last 6 throacic vertebrae, last 3 or 4 ribs, thoracolumbar fascia, and posterior iliac crest

latissimus dorsi insertion

intertubercular groove of humerus

latissimus dorsi innervation

thoracodorsal nerve (middle or long subscapular nerve), branch of the posterior cord (C6-C8)

infraspinatus

infraspinatus origin

infraspinatus fossa on posterior surface of scapula

infraspinatus insertion

greater tubercle of humerus

latissimus dorsi action

medial rotation, adduction, extension, and respiration

infraspinatus action

externally (laterally) rotate shoulder (GH joint), adduct shoulder (GH joint), and stabilize head of humerus in glenoid cavity

infraspinatus innervation

subscapular nerve (C5, C6)

supraspinatus

supraspinatus origin

supraspinatus fossa of scapula

supraspinatus insertion

greater tubercle of humerus

supraspinatus action

abduct shoulder (GH joint) and stabilize head of humerus in glenoid cavity

supraspinatus innervation

suprascapular nerve (C5, C6)

subscapularis

subscapularis origin

subscapular fossa of scapula

subscapularis insertion

lesser tubercle of humerus

subscapularis action

internally (medially) rotate shoulder (GH joint) and stabilize head of humerus in glenoid cavity

subscapularis innervation

upper and lower subscapular nerve (C5, C6)

coracobrachialis

coracobrachialis origin

coracoid process of scapula

coracobrachialis insertion

medial surface and border of body of humerus

coracobrachialis action

adduction and flexion of shoulder

coracobrachialis innervation

musculocutaneous nerve (C5-C7, mainly C7)

teres major

teres major origin

inferior angle and lower 1/3 of lateral border of scapula

teres major insertion

crest of lesser tubercle of humerus

teres major action

extension, adduction, and internal (medial) rotation of humerus (GH joint)

teres major innervation

lower subscapular nerve (C5-C7)

teres minor

teres minor origin

upper 2/3 of lateral border of scapula

teres minor insertion

greater tubercle of humerus

teres minor action

externally (laterally) rotate shoulder (GH joint), adduct shoulder (GH joint), and stabilize head of humerus in glenoid cavity

teres minor innervation

axillary nerve (C5, C6)

rhomboid major

rhomboid major origin

spinous processes of T2-T5

rhomboid major insertion

medial/vertebral border of scapula btw spine of scapula and inferior angle

rhomboid major action

adduct scapula (scapulothoracic joint), elevate scapula, and downwardly rotate scapula

rhomboid major innervation

dorsal scapular nerve (C5)

rhomboid minor

rhomboid minor origin

spinous processes of C7-T1

rhomboid minor insertion

upper portion of medial border of scapula, across from spine of scapula

rhomboid minor action

adduct scapula (scapulothoracic joint), elevate scapula, and downwardly rotate scapula

rhomboid minor innervation

dorsal scapular nerve (C5)

levator scapulae

levator scapulae origin

transverse processes of 1st-4th cervical vertebrae

levator scapulae insertion

medial border of scapula, btw superior angle and superior portion of spine of scapula

levator scapulae action

elevate scapula (scapulothoracic joint), downwardly rotate scapula, laterally flex head and neck, rotate head and neck to same side (bilaterally), extend head and neck

levator scapulae innervation

cervical (C3, C4) and dorsal scapular (C4, C5)

biceps brachii

biceps brachii origin

-short head: coracoid process of scapula

-long head: supraglenoid tubercle of scapula

biceps brachii insertion

radial tuberosity

biceps brachii action

flex elbow (humeroulnar joint), supinate forearm (radioulnar joints), and flex shoulder (GH joint)

biceps brachii innervation

musculocutaneous nerve (C5, C6)

triceps brachii

triceps brachii origin

-lateral head:posterior surface of proximal half of humerus

-long head: infraglenoid tuberosity of scapula

-medial head: posterior surface of distal half of humerus

triceps brachii insertion

olecranon process of ulna

triceps brachii action

-lateral and medial heads: extends forearm at elbow

-long head: extension of shoulder, adduction of shoulder

triceps brachii innervation

radial nerve (C6-C8)

trapezius

trapezius origin

occipital bone, ligamentum nuchae, spinous processes of T1-T12

trapezius insertion

lateral 1/3 of clavicle, acromion, and scapular spine of scapula

trapezius action

rotation, retraction, elevation, and depression of scapula, levitate clavicle, extends neck, stabilizes shoulder

trapezius innervation

accessory nerve (CN11) and cervical plexus (C3, C4)

serratus anterior

serratus anterior origin

external surfaces of upper 8-9 ribs

serratus anterior insertion

anterior surfaces of medial border of scapula

serratus anterior action

abduct scapula (scapulothoracic joint), upwardly rotate scapula, depress scapula, hold medial border of scapula against rib cage, elevate thorax during forced inhalation when fixed

serratus anterior innervation

long thoracic (C5-C7)