Muscles of Superficial Back and Pectoral Region

Trapezius origin

Superior nuchal line of occipital bone, ligamentum nuchae, and spines of C7 and T1-T12

Trapezius insertion

clavicle, acromion, and spine of scapula

Trapezius action

Upper trap: elevate and upwardly rotate scapula, extend head
Middle trap: retract scapula
Lower trap: Depress and upwardly rotate scapula

Trapezius innervation

spinal accessory nerve

Latissimus Dorsi origin

Spines of T7-T12 and L1-L5, sacrum and illium, inferior 4 ribs

Latissimus Dorsi insertion

bicipital groove of humerus

Latissimus Dorsi action

extends, abducts, and internally rotates the arm at shoulder joint. Draws arm inferiorly and posteriorly

Latissimus Dorsi innervation

Thoracodorsal nerve

Rhomboid Major origin

Spines of T2-T5

Rhomboid Major Insertion

Medial border of scapula inferior to spine

Rhomboid Major Action

Elevation, retraction and downward rotation of scapula

Rhomboid Major innervation

Dorsal scapular nerve

Rhomboid Minor origin

Spines of C7-T1

Rhomboid Minor insertion

Medial border of scapula superior to spine

Rhomboid Minor action

elevation, retraction, and downward rotation of the scapula

Rhomboid Minor innervation

dorsal scapular nerve

Levator Scapulae origin

Transverse process fo C1-C4

Levator Scapulae insertion

superior medial border of scapula

Levator Scapulae action

elevation and downward rotation of the inferior angle of scapula

Levator Scapulae innervation

dorsal scapular nerve

Muscles of superficial back

Trapezius, latissimus dorsi, rhomboid major, rhomboid minor, levator scapulae

Pectoral region muscles

Pectoralis major, pectoralis minor, serratus anterior

Pectoralis major origin

clavicle, sternum, and costal cartilages of ribs 2-6

Pectoralis major insertion

greater tuberosity and bicipital groove of humerus

Pectoralis major action

shoulder adduction and internal rotation, assists with flexion

Pectoralis major innervation

medial and lateral pectoral nerves

Pectoralis Minor origin

Ribs 3-5

Pectoralis Minor insertion

coracoid process

Pectoralis Minor action

scapular protraction and downward rotation

Pectoralis Minor innervation

medial pectoral nerve

Serratus Anterior origin

superior 9 ribs

Serratus Anterior insertion

anterior surface of the medial border of the scapula

Serratus Anterior action

scapular protraction and upward rotation

Serratus Anterior innervation

long thoracic nerve