Muscle O I A

Back 1

Sternocleidomastoid

O = Sternum and Clavicle

I = Mastoid process of temporal bone

A = Flexes neck

Back 2

Pectoralis Major

O = Clavicle and Sternum

I = Intertubercular sulcus of humerus

A = Flexes, Adducts, and Medially rotates humerus

Back 3

Pectoralis Minor

O = Ribs 3-5

I = Coracoid process of scapula

A = Depresses and Protracts scapula

Back 4

Scalenes: Anterior, Middle, Posterior

O = Transverse processes of cervical vertebrae

I = First and Second Ribs

A = Flex and Rotate neck; Assist in inspiration

Back 5

Internal and External Intercostals

O = Lower border of rib

I = Upper border of next rib

A = Elevates ribs for inspiration

Back 6

Latissimus Dorsi

O = By aponeurosis from thoracic, lumbar, and sacral spinous processes
I = Intertubercular sulcus of humerus
A = Extends, Adducts, and Medially rotates humerus

Back 7

Trapezius

O = Occipital bone, cervical and thoratic vertebrae
I = Clavicle and Spine of scapula to acromion
A = Elevates clavicle; Adducts, elevates and depresses scapula; extends head

Back 8

Levator Scapulae

O = Spines of C1-C4 vertebrae

I = Superior vertebral border of scapula

A = Elevates scapula

Back 9

Rhomboids (Major and Minor)

O = C7-T5 thoracic spinous process(- C7 to T1)

I = Vertebral border of scapula

A = Elevates and adducts scapula and rotates it downward; stabilizes scapula

Back 10

Serratus Anterior

O = Upper 8 ribs

I = Vertebral border and inferior angle of scapula

A = Rotates scapula