Muscles of Facial Expression

Originate in fascia or bones of skull and insert into the skin. Move the skin rather than a joint when
they contract.

Muscle

Origin

Insertion

Action

Buccinator

Maxilla and Mandible

Orbicularis oris

Compresses cheeks

Corrugator supercilii

Orbital rim of frontal

bone

eyebrow

Pulls skin inferiorly and

anteriorly; wrinkles
brow

Depressor anguli oris

Mandible

Angle of mouth

Depresses corner of
mouth

Depressor labii inferioris

Mandible

Skin of lower lip

Depresses lower lip

Frontalis

Galea aponeurotica

Skin of eyebrow and

bridge of nose

Raises eyebrows,
wrinkles forehead

Levator labii superioris

Maxilla

orbicularis oris

Elevates upper lip

Levator palpebrae
superioris

Tendinous band around

optic foramen

upper eyelid

Elevates upper eyelid

Mentalis

Mandible

Skin of chin

Elevates and protrudes

lower lip

Occipitalis

Occipital and Temporal

Galea aponeurotica

Tenses and retracts scalp

Orbicularis oris

Maxillary bone and

mandible

lips

Compresses, purses lips

Orbicularis oculi

Medial margin of orbit

Skin around eyelids

Closes eye

Platysma

Upper thorax between

cartilage of second rib
and acromion of scapula

Mandible and skin of

cheek

Tenses skin of neck,

depresses mandible

Risorious

Fascia over parotid

gland

angle of mouth

Draws corner of mouth

to the side

Zygomaticus major

Zygomatic bone

Angle of mouth

Retracts and elevates

corner of mouth

Extrinsic Eye
The movement of the eyeballs are controlled by three pairs of extrinsic muscles. The superior and inferior
recti muscles control vertical movements and the lateral and medial recti muscles move the eyeball laterally.
The superior oblique muscle moves the eyeball inferiorly and laterally and the inferior oblique muscle
moves the eyeball superiorly and laterally.

Muscle

Origin

Insertion

Action

Superior rectus

Sphenoid bone around optic

canal

Superior surface of eyeball

Eye looks up

Inferior rectus

As above

Inferior, medial surface of eye

Eye looks down

Lateral rectus

As above

Lateral surface of eyeball

Eye rotates laterally

Medial rectus

As above

Medial surface of eyeball

Eye rotates medially

Superior oblique

As above

Superior, lateral surface of

eyeball

Eye rolls, looks down and to

the side

Inferior oblique

Maxillary bone at anterior

portion of orbit

Inferior, lateral surface of

eyeball

Eye rolls, looks up and to the

side

Muscles of Mastication
These four muscles move the mandible and are involved in chewing. Three of them, masseter,
temporalis and medial pterygoid are powerful closers of the joint and account for the strenth of the
bite. The medial and lateral pterygoids move the mandible from side to side and also protrude the
mandible.

Muscle

Origin

Insertion

Action

Masseter

zygomatic arch

Mandible

Elevates mandible

Temporalis

Temporal and frontal

bones

Mandible

Elevates mandible

Medial pterygoid

Sphenoid (Lateral
pterygoid plate)

Mandible

Elevates mandible;
moves mandible side to
side

Lateral pterygoid

Sphenoid (Lateral
pterygoid plate)

Mandible

Opens jaws, protrudes

mandible; moves
mandible side to side

Muscles of the Floor of the Mouth

These muscles are part of the suprahyoid (above the hyoid) group of muscles. Together with the
infrahyoid muscles (discussed below) these muscles fix the hyoid bone and this enables the hyoid bone
to serve as a firm base for the attachment of the tongue. As a group these muscles also elevate the
hyoid bone, the floor of the oral cavity, and tongue during swallowing.

Muscle

Origin

Insertion

Action

Digastric

Anterior belly from

mandible and posterior
belly from temporal

Hyoid

Elevates hyoid and/or

depresses mandible

Stylohyoid

Temporal (styloid
process)

Hyoid

Elevates larynx

Mylohyoid

Mandible

Hyoid

Elevates hyoid and floor

of mouth; depresses
mandible

Extrinsic Muscles of the Larynx

The extrinsic muscles of the larynx are also called infrahyoid muscles because they lie inferior to the
hyoid bone. These muscles are sometimes called "strap" muscles because of their ribbonlike
appearance. These muscles depress the hyoid bone and larynx during swallowing and speech.

Muscle
Omohyoid

Origin

Insertion

Central tendon attaches One belly attaches to

to clavicle and 1st rib hyoid; second to scapula

Action
Depresses hyoid and
larynx

Sternohyoid

Clavicle and Sternum

Hyoid

As above

Sternothyroid

Sternum

Thyroid cartilage

As above

Thyrohyoid

Thyroid cartilage

Hyoid

Depresses hyoid;
elevates thyroid

Muscles that Move the Head

Balance and movement of the head on the atlanto-occipital joint involves the action of several neck
muscles. One example of these muscles is the sternocleidomastoid muscles.

Muscle

Sternocleidomastoid

Origin

Sternum and clavicle

Insertion

Action

Temporal (mastoid
process)

Together, flexes the

neck; alone, one side
bends head toward
shoulder and turns face
to opposite side

Muscles that Move the Abdominal Wall

Four muscles contribute to the abdominal wall. Three are flat, the external oblique, the internal
oblique and the transversus abdominis, and one is a straplike muscle, the rectus abdominis. The fibers
in each of these muscles run in a cross direction from one another in a way that maximizes the
strength of the three muscles together (think of plywood). The aponeuroses of three muscles, external
oblique, internal oblique and transversus abdominis meet at the midline to form the linea alba. The
linea alba is a tough fibrous band of tissue that extends from the xiphoid process to the pubic
symphysis.

Muscle

Origin

Insertion

Action

Rectus abdominis

Pubic (crest and symphysis)

Cartilage of ribs (5-7) and

xiphoid process

Flexes vertebral column,

depresses ribs and compresses
abdomen

External abdominal oblique

External and inferior borders of

ribs 5-12

Iliac crest and linea alba

Compresses abdomen;
depresses ribs; flexes, laterally
flexes or rotates vertebral
column

Internal abdominal oblique

Lumbodorsal fascia and iliac

crest

Inferior surfaces of ribs 9-12,

costal cartilages 8-10, linea
alba, and pubis

As above

Transversus abdominis

Cartilages of inferior ribs, iliac

crest, and lumbodorsal fascia

Linea alba and pubis

Compresses abdomen

Muscles Used in Ventilation (Breathing)

These muscles alter the size of the thoracic cavity during breathing. The diaphragm is the most
important. It is domed shaped and consists of two parts: a peripheral muscular portion and a
tendinous central portion called the central tendon upon which the muscle fibers insert. Two other
muscles, external intercostals and internal intercostals, occupy the spaces between the ribs. The fibers
of the external intercostals run obliquely inferiorly and anteriorly and the fibers of the internal
intercostals run obliquely inferiorly and posteriorly.

Muscle

Origin

Insertion

Action

Diaphragm

Xiphoid process, ribs 7-12

and associated costal
cartilages, and lumbar
vertebrae

Central tendinous sheet

Contraction expands thoracic

cavity, compresses
abdominopelvic cavity

External intercostals

inferior border of each rib

Superior border of next rib

below

Elevates ribs

Internal intercostals

Superior border of each rib

Inferior b order of previous rib

Depress ribs

above
Quadratus lumborum

Iliac crest and iliolumbar

ligament

Twelfth rib and transverse

processes of L1 to L4

Together they depress ribs;

one side alone produces
lateral flexion of vertebral
column

Muscles of the Pelvic Floor

The levator ani muscle along with a second muscle forms the pelvic floor. These muscles form the
pelvic diaphragm which supports and maintains the position of the pelvic viscera. The levator ani
muscle is divisible into two parts, the pubococcygeus and iliococcygeus muscles.

Muscle

Levator ani

Origin

Pubis and ischial spine

Insertion

Action

Tenses floor of pelvis,

supports pelvic organs,
Coccyx and median raphe
flexes coccyx, elevates
and retracts anus

External anal sphincter

Via tendon from coccyx

Encircles anal opening

Closes anal opening

Muscles that Move the Pectoral Girdle

These muscles can be grouped into the anterior muscles the move the pectoral girdle and the
posterior muscles. The muscles stablize the pectoral girdle so that it can serve as a stable platform on
which the humerus can move. These muscles will also adjust the position of the pectoral girdle and
particularly the scapula to allow for a wider range of movements for the humerus.
The anterior muscles are the subclavius, pectoralis minor and the serratus anterior and the posterior
muscles are the trapezius, levator scapulae, rhomboideus major and rhomboideus minor.

Origin
Muscle

Insertion

Action

Subclavius

First rib

Clavicle

Depresses and protracts

shoulder

Pectoralis minor

Ventral surfaces of ribs 3-5

Scapula

Depresses and protracts

shoulder, rotates scapula
downward, elevates ribs

Serratus anterior

Anterior and superior margins

of ribs 1-9

Scapula

Protracts shoulder and rotates

scapula upward

Trapezius

Occipital bone, ligamentum

nuchae, spinous processes of
thoracic vertebrae

Clavicle and scapula

May elevate, retract, depress, or

rotate scapula upward; elevate
clavicle; extend neck

Levator scapulae

First 4 cervicle vertebrae

Scapula

Elevates scapula

Rhomboideus major

Spines of T2 -T5

Scapula

adducts scapula and rotates it

downward

Rhomboideus minor

Spines of C7 and T1

Scapula

As above

Muscles that Move the Arm

Nine muscles cross the shoulder joint. Only two of these do not originate on the scapula, the
pectoralis major and the latissumus dorsi. Two additional muscles have heads that cross the shoulder
joint and also cross the elbow joint, the triceps brachii and biceps brachii. These two muscles will be
treated in the next group. Four muscles the subscapularis, supraspinatus, infraspinatus and teres minor
for the rotator (musclotendinous) cuff which helps to stabilize the shoulder joint.

Muscle

Origin

Insertion

Action

Pectoralis major

Clavicle and sternum

Humerus

Flexion, adduction and

medially rotation of arm

Latissimus dorsi

Spines of lower thoracic and all

lumbar vertebrae, ribs 8-12,
lumbodorsal fascia

Humerus

Extension, adduction and

medially rotation of the arm

Deltoid

Clavicle and scapula

Humerus

Abduction at shoulder, also

extension, flexion, medial and
lateral rotation

Subscapularis

Scapula

Humerus

Medial rotation at shoulder

joint

Supraspinatus

Scapula

Humerus

Abduction at shoulder joint

Infraspinatus

Scapula

Humerus

Lateral rotation at shoulder

joint

Teres major

Scapula

Humerus

Extension, adduction and

medial rotation at shoulder joint

Teres minor

Scapula

Humerus

Lateral rotation at shoulder

joint

Coracobrachialis

Scapula

Humerus

Adduction and flexion at

shoulder joint

Muscles that Move the Forearm

These muscles are involved of flexion and extension of the forearm at the elbow joint.

Muscle

Origin

Insertion

Action

Biceps brachii

Scapula

Radius

Flexion at elbow and shoulder,

supinates forearm

Brachialis

Humerus

Ulna

Flexes elbow

Brachioradialis

Humerus

Radius

Flexes elbow

Triceps brachii

Scapula and Humerus

Ulna

Extends elbow

Anconeus

Humerus

Ulna

Extends elbow

Muscles that Move the Wrist, Hand and Digits

This group is know as the extrinsic muscles that move the wrist, hand and digits because they
originate outside the hand and insert within it. There are also intrinsic muscles of the hand which will
not be covered in this course. These muscles can be divided into two groups on the basis of location
and function. The muscle of the anterior compartment (arm in anatomical position) function as
flexors while the muscles of the posterior compartment function as extensors.

Muscle

Origin

Insertion

Action

Flexor carpi radialis

Humerus

Metacarpals 2 and 3

Flexes and abducts wrist

Palmaris longus

Humerus

Flexor retinaculum and palmar

aponeurosis

Flexes wrist

Humerus, ulna and radius

Flexion at proximal
Middle phalanges of fingers 2interphalangeal joint,
5
metocarpophalangeal joint and
wrist joint

Flexor digitorum profundus

Ulna

Flexion at distal and proximal

interphalangeal joints,
Distal phalanges of fingers 2-5
metocarpophalangeal joint and
wrist joint

Flexor carpi ulnaris

Humerus and ulna

Flexor digitorum superficialis

Pisiform, hamate and

metacarpal 5

Flexes and adducts wrist

Extensor carpi radialis

Humerus

Metacarpal 2 and 3

Extends and abducts wrist

Extensor digitorum

Humerus

Posterior surfaces of phalanges

of finger 2-5

Extension at joints of fingers

and wrist

Extensor digiti minimi

Humerus

Posterior surface of proximal

phalanx of little finger

Extends joint of little finger

Extensor carpi ulnaris

Humerus and ulna

Metacarpal 5

Extends and adducts wrist

Muscles that Move the Femur

These muscles are larger and more powerful than those of the upper limb because they provide
stability, enable locomotion and maintain posture.
Muscle

Origin

Insertion

Action

Psoas major

Vertebrae T12-L5

Femur

Flexes hip and/or lumbar spine

Illiacus

Ilium

Femur

As above

Gluteus maximus

Ilium, sacrum, coccyx and

lumbodorsal fascia

Iliotibial tract and femur

Extension and lateral rotation at

the hip

Gluteus medius

Ilium

Femur

Abduction and medial rotation

at the hip

Gluteus minimus

Ilium

Femur

As above

Tensor fasciae latae

Ilium

Iliotibial tract

Flexion and medial rotation at

hip; tenses fascia lata

Piriformis

Sacrum

Femur

Lateral rotation and abduction

at thigh

Obturator internus

Lateral and medial margins of

obturator foramen

Femur

Lateral rotation at the hip

Obturator externus

As above

Femur

As above

Superior gemellus

Ischium

Femur

As above

Inferior gemellus

Ischium

Femur

As above

Quadratus femoris

Ischium

Femur

As above

Adductor longus

Pubis

Femur

Adduction, flexion, and medial

rotation at hip

Adductor brevis

Pubis

Femur

As above

Adductor magnus

Pubis and Ischium

Femur

As above but also inferior

portion produces extension and
lateral rotation at hip

Pubis

Femur

Flexion, medial rotation and

adduction at hip

Muscle

Origin

Insertion

Action

Rectus femoris

Ilium

Tibia

Extends knee; flexes hip

Vastus lateralis

Femur

Tibia

Extends knee

Vastus medialis

Femur

Tibia

Extends knee

Vastus intermedius

Femur

Tibia

Extends knee

Gracilis

Pubis

Tibia

Flexes knee; adduction and

medial rotation at hip

Sartorius

Ilium

Tibia

Flexes knee; flexion and lateral

rotation at hip

Biceps femoris

Ischium and Femur

Fibula and tibia

Flexes knee; extends and

laterally rotates hip

Semitendinosus

Ischium

Tibia

Flexes knee; medially rotates

Pectineus

Muscles that Move the Leg

leg; extends hip

Semimembranosus

Ischium

Tibia

As above

Muscles that Move the Foot and Toes

Muscle

Origin

Insertion

Action

Tibialis anterior

Tibia

First metatarsal and first

cuneiform

Dorsiflexes ankle and inverts

foot

Extensor hallucis longus

Fibula

Distal phalanx of great toe

extends joints of great toe

Extensor digitorum longus

Tibia and fibula

phalanges of toes 2-5

extends joints of toes 2-5

Peroneus longus

Tibia and fibula

First metatarsal and first

cuneiform

Plantar flexes ankle and everts

foot

Peroneus brevis

Fibula

Fifth metatarsal

Plantar flexes ankle and everts

foot

Gastrocnemius

Femur

Calcaneus (via calcaneal

tendon)

Plantar flexes ankle; inverts and

adducts foot; flexes knee

Soleus

Fibula and tibia

Calcaneus (via calcaneal

Plantar flexes ankle

tendon)