Origins, Insertions, and Actions of Muscles

External Abdominal Oblique Origin

Lower 8 ribs

External oblique insertion

linea alba

External oblique Primary action

flexion of the spine

Internal abdominal oblique origin

lumbar fascia

Internal oblique insertion

linea alba

Internal oblique primary action

flexion of the spine

rectus abdominis origin

pubic symphysis

rectus abdominis insertion

xiphoid process

rectus abdominis primary action

flex & rotate lumbar spine

Sternocleidmastoid origin

manubrium

sternocleidmastoid insertion

mastoid process

sternocleidomastoid primary action

rotation of the head

Pectoralis minor origin

anterior surface of ribs 3-5

Pectoralis minor insertion

coracoid process of scapula

pectoralis minor primary action

draws scapula forward and down

pectoralis major origin

sternum

pectoralis major insertion

intertubercular sulcus

pectoralis major primary action

adducts the arm

erector spinae origin

iliac crest

erector spinae insertion

thoracic/cervical transverse processes

erector spinae primary action

extension of spine

trapezius origin

occipital bone

trapezius insertion

acromion process

trapezius primary action

retracts and rotates scapula

latissimus dorsi origin

lumbar vertebrae

latissimus dorsi insertion

humerus

latissimus dorsi primary action

adduction of arm

levator scapulae origin

transverse processes of C1-C4

levator scapulae insertion

superior medial border of scapula

levator scapulae primary action

adduction of scapula

deltoid origin

clavicle

deltoid insertion

deltoid tuberosity of humerus

deltoid primary action

arm abduction

supraspinatus origin

supraspinous fossa

supraspinatus insertion

greater tubercle of humerus

supraspinatus primary action

initiates arm abduction

infraspinatus origin

infraspinous fossa of scapula

infraspinatus insertion

greater tubercle of humerus

infraspinatus primary action

rotates arm laterally

subscapularis origin

subscapular fossa

subscapularis insertion

lesser tubercle of humerus

subscapularis primary action

rotates arm medially

biceps brachii origin

coracoid process of scapula

biceps brachii insertion

radial tuberosity

biceps brachii primary action

flexion of forearm

brachialis origin

humerus

brachialis insertion

coranoid process of ulna

brachialis primary action

flexion of forearm

triceps brachii origin

humerus

triceps brachii insertion

olecranon process of ulna

triceps brachii primary action

forearm extensor

extensor carpi radialis origin

humerus

extensor carpi radialis insertion

2nd metacarpal

extensor carpi radialis primary action

extension of hand

extensor carpi ulnaris origin

lateral epicondyle of humerus

extensor carpi ulnaris insertion

5th metacarpal

extensor carpi ulnaris primary action

extension of hand

extensor digitorum origin

lateral epicondyle of humerus

extensor digitorum insertion

distal phalanges of 2nd to 5th fingers

extensor digitorum primary action

finger extension

flexor carpi radialis origin

medial epicondyle of humerus

flexor carpi radialis insertion

2nd & 3rd metacarpals

flexor carpi radialis primary action

flexion of hand

flexor carpi ulnaris origin

medial epicondyle of humerus

flexor carpi ulnaris insertion

carpal bones

flexor carpi ulnaris action

flexion of hand

flexor digitorum origin

medial epicondyle of humerus

flexor digitorum insertion

middle phalanges of 2nd to 5th fingers

flexor digitorum action

flexion of fingers