origin, insertion, and action

Frontalis origin

Epicranial aponeurosis

Frontalis insertion

Skin of the eyebrows and root of the nose

Frontalis action

Raises the eyebrows and wrinkles the forehead

Occipitalis origin

Occipital and temporal bones

Occipitalis insertion

Epicranial aponeurosis

Occipitalis action

Fixes aponeurosis and pulls scalp posteriorly

Orbicularis oculi origin

Frontal and maxillary bones and ligaments around orbit

Orbicularis oculi insertion

Tissue of the eyelid

Orbicularis oculi action

Closes the eye

Orbicularis oris origin

Maxillae and mandible

Orbicularis oris insertion

Muscle and skin at angles of the mouth

Orbicularis oris action

Closes lips

Temporalis origin

Temporal fossa

Temporalis insertion

Coronoid process of the mandible

Temporalis action

Closes jaw

Sternocleidomastoid origin

Manubrium of sternum and medial portion of the clavicle

Sternocleidomastoid insertion

Mastoid process of temporal bone and superior nuchal line of the occipital lobe

Sternocleidomastoid action

Flexes and laterally rotates the head

Sternohyoid origin

Manubrium of sternum and medial portion of the clavicle

Sternohyoid insertion

Lower margin of the hyoid bone

Sternohyoid action

Depresses larynx and hyoid bone if mandible is fixed

External intercostals origin

Inferior border of rib above

External intercostals insertion

Superior border of rib below

External intercostals action

Depresses ribs

Internal intercostals origin

Superior border of the rib below

Internal costal insertion

Inferior border of the rib above

Internal intercostals action

Elevates ribs

Diaphragm origin

Inferior internal surface of the rib cage and sternum, costal cartilages of last 6 ribs and lumbar vertebrae

Diaphragm insertion

Central tendon

Diaphragm action

Prime mover of inspiration

Pectoralis major origin

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

Pectoralis major insertion

Intertubercular sulcus and greater tubercle groove of humerus

Pectoralis major action

Adducts and medially rotates arm

Deltoid origin

clavicle, acromion, and spin of scapula

Deltoid insertion

Deltoid tuberosity

Deltoid action

Prime mover of arm abduction

Supraspinatus origin

Supraspinous fossa

Supraspinatus insertion

Superior part of greater tubercle of the humerus

Supraspinatus action

Initiates abduction of arm

Terse minor origin

Lateral border of dorsal scapular surface

Terse minor insertion

Greater tubercle of humerus

Terse minor action

Rotates arm laterally

Infraspinatus origin

Infraspinous fossa

Infraspinatus insertion

Greater tubercle of humerus

Infraspinatus action

Rotates arm laterally

Subscapularis origin

Subscapulara fossa

Subscapulara insertion

Lesser tubercle of humerus

Subscapularis action

Rotates arm medially

Biceps brachii origin

Short head: coracoid process; long head: supraglenoid tubercle and lip of glenoid cavity

Biceps brachii insertion

Radial tuberosity

Biceps brachii action

Flexes and supinates forearm

Triceps brachii origin

Long head: infraglenoid tubercle; lateral head: posterior shaft of humerus; medial head: posterior shaft of humerus

Triceps brachii insertion

Olecranon process of ulna

Triceps brachii action

Powerful forearm extensor

Rectus femoris origin

Anteriori inferior illiac spine and superior margin of acetabulum

Rectus femoris insertion

Tibial tuberosity

Rectus femoris action

Extends leg and flexes thigh at hip

Vastus lateralis origin

Greater trochanter, intertrochantric line, and linea aspera

Vastus lateralis insertion

Tibial tuberosity

Vastus lateralis action

Extends leg and stabilizes knee

Vastus medialis origin

Intertrochantric line, linea aspera, and medial supracondyler line

Vastus medialis action

Extends leg

Vastus intermedius origin

Anterior and lateral surface of proximal femur shaft

Vastus intermedius insertion

Tibial tuberosity

Vastus intermedius action

Extends leg

Biceps femoris origin

Ischial tuberosity, linea aspera, lateral supercondylar line, and distal femur

Biceps femoris insertion

Head of tibia and lateral condyle of fibula

Biceps femoris action

Extends thigh and flexes leg

Semitendinosus origin

Ischial tuberosity

Semitendinosus insertion

Medial aspect of upper tibial shaft

Semitendinosus action

Extends thigh and flexes leg

Semimembranosus origin

Ischial tuberosity

Semimembranosus insertion

Medial condyle of tibia

Semimembranosus action

Extends thigh and flexes leg

Gastrocnemius origin

Medial and lateral condyle of femur

Gastrocnemius insertion

Posterior calcaneus

Gastrocnemius action

Plantar flexes foot