Anatomy Lab (muscles origin, insertion, and action)

masseter origin

zygomatic arch and zygomatic bone

masseter insertion

angle and ramus of mandible

masseter action

primer mover of jaw closure

mylohyoid origin

medial surface of mandible

mylohyoid insertion

hyoid bone and median raphe

mylohyoid action

elevates hyoid bone and floor of mouth

pectoralis major origin

clavicle, sternum, cartilage of ribs 1-6, and aponeurosis of external oblique

pectoralis major insertion

intertubercular sulcus of humerus

pectoralis major action

arm flexion; adducts, medially rotates arm

deltoid origin

clavicles; acromion and spine of scapula

deltoid insertion

deltoid tuberosity of humerus

deltoid action

arm abduction

rectus abdominis origin

pubic crest and symphysis

rectus abdominis insertion

xiphoid process and costal cartilages of ribs 5-7

rectus abdominis action

flexes vertebral column

latissimus dorsi origin

spinous process of thoracic vertebrae, lumbar vertebrae, last few ribs, and iliac crest

latissimus dorsi insertion

intertubercular sulcus of humerus

latissimus dorsi action

arm extension; adducts and medially rotates arm

levator scapulae origin

transverse process of C1-C4

levator scapulae insertion

scapula

levator scapula action

elevates and adducts scapula

semispinalis origin

transverse process of C7-T12

semispinalis insertion

occipital bone and spinous process of cervical vertebrae and T1-T4

semispinalis action

extend head and vertebral column; rotate toward opposite side

erector spinae origin

iliac crest, lumbar, thoracic, and cervical vertebrae, and/or ribs 3-6

erector spinae insertion

ribs and vertebrae about six segments above origin

erector spinae action

extend and laterally flex spine, extends and rotates head

triceps brachii origin

glenoid cavity, humerus

triceps brachii insertion

olecranon of ulna

triceps brachii action

forearm extensor

biceps brachii origin

coracoid process; glenoid cavity, supraglenoid tubercle, intertubercular sulcus

biceps brachii insertion

radial tuberosity

biceps brachii action

flexion and supination of forearm

brachialis origin

humerus

brachialis insertion

ulna

brachialis action

flexor of forearm

sartorius origin

iliac spine

sartorius insertion

tibia

sartorius action

flexes, abducts, and laterally rotates thigh; flexes leg

gracilis origin

pubis

gracilis insertion

tibia

gracilis action

adducts thigh; flexes and medially rotates leg

rectus femoris origin

iliac spine and acetabulum

rectus femoris insertion

tibial tuberosity and patella

rectus femoris action

extends leg and flexes thigh

gluteus medius origin

ilium

gluteus medius insertion

femur

gluteus medius action

abducts and medially rotates thigh

biceps femoris origin

ischium, femur

biceps femoris insertion

fibula, tibia

biceps femoris action

extends thigh and flexes leg

semitendinosus origin

ischium

semitendinosus insertion

tibia

semitendinosus action

extends thigh; flexes leg