MUSCLES IN THE SYSTEM

buccinator

buccinator

origin: maxilla and mandible

insertion: orbicularis oris at the corner of the mouth

action: draws corner of mouth posteriorly; compresses cheek to hold food between teeth

depressor anguli oris

origin: lower border of mandible

insertion: skin of lip near corner of mouth

action: lowers corner of mouth; frown

levator labii superioris

origin: maxilla

insertion: skin and orbicularis oris of upper lip

action: raises upper lip; sneer

occipitofrontalis

origin: occipital bone

insertion: skin of eyebrow and nose

action: moves scalp; raises eyebrows

orbicularis oculi

origin: maxilla and frontal bones

insertion: circles orbit and inserts onto skin around eyelids

action: closes eyes: blinking, winking, squinting

orbicularis oris

origin: nasal septum, maxilla, and mandible

insertion: fascia and other muscle of lips

action: closes and purses lips, kissing

zygomaticus major

origin: zygomatic bone

insertion: angle of mouth

action: elevates and abducts upper lip and corner of mouth; smile

zygomaticus minor

origin: zygomatic bone

insertion: orbicularis oris of upper lip

action: elevates and abducts upper lip; smile

temporalis

origin: temporal fossa

insertion: anterior portion of mandibular ramus and coronoid process

action: elevates and draws mandible posteriorly; closes jaw

masseter

origin: zygomatic arch

insertion: lateral side of mandibular ramus

action: elevates and pushes mandible anteriorly; closes jaw

lateral pterygoid

origin: lateral pterygoid plate and greater wing of sphenoid

insertion: condylar process of mandible and articular disk

action: pushes mandible anteriorly and depresses mandible; closes jaw

medial pterygoid

origin: lateral pterygoid plate of sphenoid and tuberosity of maxilla

insertion: medial surface of mandible

action: pushes mandible anteriorly and elevates mandible; closes jaw

intrinsic

tongue muscle

origin: inside tongue

insertion: inside tongue

action: changes shape of tongue

extrinsic

tongue muscle

origin: bones around oral cavity or soft palate

insertion: onto tongue

action: moves tongue

suprahyoid

hyoid muscle

(e.g., geniohyoid, stylohyoid, and hyoglossus)

origin: base of skull, mandible

insertion: hyoid bone

action: elevates or stabilizes hyoid

infrahyoid

hyoid muscle

(e.g., thyrohyoid)

origin: sternum, larynx

insertion: hyoid bone

action: depresses or stabilizes hyoid

soft palate muscles

origin: skull or soft palate

insertion: palate, tongue, or pharynx

action: moves soft palate, tongue, or pharynx

elevators

pharyngeal muscles

origin: soft palate and auditory tube

insertion: pharynx

action: elevate pharynx

constrictors

pharyngeal muscles

origin: soft palate and auditory tube

insertion: pharynx

action: constrict pharynx

other pharyngeal muscles

superior, middle, and inferior

flexors

deep neck muscle

origin: anterior side of vertebrae

insertion: base of skull

action: flex head and neck

extensors

deep neck muscles

origin: posterior side of vertebrae

insertion: base of skull

action: extend head and neck

sternocleidomastoid

deep neck muscles

origin: manubrium of sternum and medial part of clavicle

insertion: mastoid process and nuchal line of skull

action: individually rotate head; together flex neck

trapezius

deep neck muscles

origin: posterior surface of skull and upper vertebral column (c7-t12)

insertion: clavicle, acromion process and scapular spine

action: extends and laterally flexes neck

erector spinae

(three columns: iliocostalis, longissimus, spinalis)

superficial muscle

origin: sacrum, ilium, vertebrae, and ribs

insertion: ribs, vertebrae, and skull

action: extends vertebral column; maintains posture

deep back muscles

origin: vertebrae

insertion: vertebrae

action: extend vertebral column and help bend vertebral column laterally

scalenes

origin: cervical vertebrae

insertion: first and second ribs

action: inspiration; elevate ribs

external intercostals

origin: inferior edge

insertion: superior edge of next rib below origin

action: inspiration; elevate ribs

internal intercostals

origin: superior edge of each rib

insertion: inferior edge of next rib above origin

action: forced expiration; depress ribs

diaphragm

origin: inferior ribs, sternum, and lumbar vertebrae

insertion: central tendon of diaphragm

action: inspiration; depress floor of thorax

rectus abdominis

origin: pubic crest and pubic symphysis

insertion: xiphoid process and inferior ribs

action: flexes vertebral column; compresses abdomen

external abdominal oblique

origin: ribs 5-12

insertion: iliac crest, inguinal ligament, and fascia of rectus abdominis

action: compresses abdomen; flexes and rotates vertebral column

internal abdominal oblique

origin: iliac crest, inguinal ligament, and lumbar fascia

insertion: ribs 10-12 and fascia of rectus abdominus

action: compresses abdomen; flexes and rotates vertebral column

transversus abdominis

origin: costal cartilages 7-12, lumbar fascia, iliac crest, and inguinal ligament

insertion: xiphoid process, fascia of rectus abdominis, and pubic tubre

action:

coccygeus

origin: ischial spine

insertion: coccyx

action: forms pelvic floor; supports pelvic organs

levator ani

origin: posterior pubis and ischial spine

insertion: sacrum and coccyx

action: elevates anus; supports pelvic organs

bulbospongiosus male

urogenital triangle

origin: central tendon of perineum and median raphe of penis

insertion: dorsal surface of penis and bulb of penis

action: compresses base of penis; ejects urine or semen; erects penis

bulbospongiosus female

urogenital triangle

origin: central tendon of perineum

insertion: base of clitoris

action: erects clitoris

ischiocavernosus

origin: ischial ramus

insertion: corpus cavernosum

action: compresses base of penis or clitoris

external urethral sphincter

origin: pubic ramus

insertion: median raphe

action: constricts urethra to stop urine flow

deep

transverse perineal muscle

origin: ischial ramus

insertion: median raphe

action: supports pelvic floor

superficial

transverse perineal muscle

origin: ischial ramus

insertion: central perineal

action: fixes central tendon

external anal sphincter

anal triangle

origin: coccyx

insertion: central tendon of perineum

action: keeps orifice of anal canal closed; relaxes during defecation

levator scapulae

origin: transverse processes of c1-c4

insertion: superior angle of scapula

action: elevates, retracts, and rotates scapula; laterally flexes neck

pectoralis minor

origin: ribs 3-5

insertion: coracoid process of scapula

action: depresses scapula or elevates ribs

rhomboids major

origin: spinous processes of t1-t4

insertion: medial border of scapula

action: retracts, rotates, and fixes scapula

rhomboids minor

origin: spinous processes t1-t4

insertion: medial border of scapula

action: retracts, slightly elevates, rotates, and fixes scapula

serratus anterior

origin: ribs 1-9

insertion: medial border of scapula

action: rotates and protracts scapula; elevates ribs

trapezius

origin: posterior surface of skull and spinous processes of c7-t12

insertion: clavicle, acromion process, and scapular spine

action: elevates, depresses, retracts, rotates, and fixes scapula; extends neck

deltoid

origin: clavicle, acromion process, and scapular spine of scapula

insertion: deltoid tuberosity of humerus

action: flexes and extends shoulder; abducts and medially and laterally rotates arm

latissimus dorsi

origin: spinous process of t7-l5, sacrum and iliac crest, and inferior angle of scapula in some people

insertion: medial crest of intertubercular groove of humerus

action: extends shoulder; adducts and medially rotates arm

pectoralis major

origin: clavicle, sternum, superior six costal cartilages, and abdominal muscles

insertion: lateral crest of intertubercular groove of humerus

action: flexes shoulder; extends shoulder from flexed position; adducts and medially rotates arm

teres major

origin: lateral border of scapula

insertion: medial crest of intertubercular groove of humerus

action: extends shoulder from flexed position; adducts and medially rotates arm

infraspinatus

rotator cuff

origin: infraspinous fossa of scapula

insertion: greater tubercle of humerus

action: stabilizes and extends shoulder and laterally rotates arm

subscapularis

rotator cuff

origin: subscapular fossa of scapula

insertion: lesser tubercle of humerus

action: stabilizes and extends shoulder and medially rotates arm

supraspinatus

rotator cuff

origin: supraspinous fossa of scapula

insertion: greater tubercle of humerus

action: stabilizes shoulder and adducts arm

teres minor

rotator cuff

origin: lateral border of scapula

insertion: greater tubercle of humerus

action: stabilizes and extends shoulder; adducts and laterally rotates arm

biceps brachii

origin: long head- supraglenoid tubercle of scapula

short head- coracoid process of scapula

insertion: radial tuberosity and aponeurosis of biceps branchii

action: flexes elbow; supinates forearm; flexes shoulder

brachialis

origin: anterior surface of humerus

insertion: coronoid process of ulna

action: flexes elbow

triceps brachii

origin: long head- lateral border of scapula

lateral head- lateral and posterior surface of humerus

medial head- posterior humerus

insertion: olecranon process of ulna

action: extends elbow; extends shoulder; adducts arm

palmaris longus

anterior forearm

origin: Medial epicondyle of humerus

insertion: Aponeurosis over palm

action: Tightens skin

flexor carpal radialis

anterior forearm

origin: Medial epicondyle of humerus

insertion: Second and third metacarpal bones

action: flexes and abducts wrist

flexor carpal ulnaris

anterior forearm

origin: Medial epicondyle of humerus and ulna

insertion: Pisiform

action: Flexes and adducts wrist

flexor digitorum profundus

anterior forearm

origin: Ulna

insertion: Distal phalanges of digits 2–5

action: Flexes fingers and wrist

flexor digitorum superficialis

anterior forearm

origin: Medial epicondyle of humerus, coronoid process, and radius

insertion: Middle phalanges of digits 2–5

action: Flexes fingers and wrist

pronator quadratus

origin: distal ulna

insertion: Distal radius

action: Pronates forearm

pronator teres

origin: Medial epicondyle of humerus and coronoid process of ulna

insertion: Radius

action: Pronates forearm

brachioradialis

posterior forearm

origin: Lateral supracondylar ridge of humerus

insertion: Styloid process of radius

action: Flexes elbow

Extensor carpi radialis brevis

posterior forearm

origin: Lateral epicondyle of humerus

insertion: Base of third metacarpal bone

action: Extends and abducts wrist

Extensor carpi radialis longus

posterior forearm

origin: Lateral supracondylar ridge of humerus

insertion: Base of second metacarpal bone

action: Extends and abducts wrist

Extensor carpi ulnaris

posterior forearm

origin: Lateral epicondyle of humerus and ulna

insertion: Base of fifth metacarpal bone

action: Extends and adducts wrist

extensor digitorum

posterior forearm

origin: Lateral epicondyle of humerus

insertion: Extensor tendon expansion over phalanges of digits 2–5

action: Extends fingers and wrist

supinator

origin: Lateral epicondyle of humerus and ulna

insertion: Radius

action: Supinates forearm (and hand)

Iliopsoas

origin: Iliac fossa and vertebrae T12–L5

insertion: Lesser trochanter of femur and hip capsule

action: Flexes hip

gluteus maximus

origin: Posterior surface of ilium, sacrum, and coccyx

insertion: Gluteal tuberosity of femur and iliotibial tract

action: Extends hip; abducts and laterally rotates thigh

Gluteus medius

origin: Posterior surface of ilium

insertion: Greater trochanter of femur

action: Abducts and medially rotates thigh

gluteus minimus

origin: Posterior surface of ilium

insertion: Greater trochanter of femur

action: Abducts and medially rotates thigh

tensor fasciae latae

origin: Anterior superior iliac spine

insertion: Through lateral fascia of thigh to lateral condyle of tibia

action: Steadies femur on tibia through iliotibial tract when standing; flexes hip; medially rotates and abducts thigh

Quadriceps femoris

anterior compartment

insertion: Tibial tuberosity via patellar ligament

action: Extends knee; flexes hip

Rectus femoris

origin: Ilium

insertion: Tibial tuberosity via patellar ligament

action: Extends knee; flexes hip

vastus lateralis

anterior compartment

origin: Greater trochanter and linea aspera of femur

insertion: Tibial tuberosity via patellar ligament

action: Extends knee

vastus medialis

anterior compartment

origin: Linea aspera of femur

insertion: Tibial tuberosity via patellar ligament

action: Extends knee

vestus intermedius

anterior compartment

origin: body of femur

insertion: tibial tuberosity via patellar ligament

action: extends knee

Sartorius

anterior compartment

origin: Anterior superior iliacspine

insertion: Medial side of tibial tuberosity

action: Flexes hip and knee; laterally rotates thigh

adductor longus

medial compartment

origin: Pubis

insertion: Linea aspera of femur

action: Adducts and laterally rotates thigh; flexes hip

adductor magnus

medial compartment

origin: Pubis and ischium

insertion: Femur

action: Adducts and laterally rotates thigh; extends knee

gracilis

medial compartment

origin: Pubis near symphysis

insertion: Tibia

action: Adducts thigh; flexes knee

biceps femoris

posterior compartment

origin: Long head—ischial tuberosity short head- femur

insertion: Head of fibula

action: Flexes knee; laterally rotates leg; extends hip

semimembranous

posterior compartment

origin: Ischial tuberosity

insertion: Medial condyle of tibia and collateral ligament

action: Flexes knee; medially rotates leg; extends hip

semitendinosus

posterior compartment

origin: Ischial tuberosity

insertion: Tibia

action: Flexes knee; medially rotates

leg; extends hip

extensor digitorum longus

anterior compartment

origin: Lateral condyle of tibia and fibula

insertion: Four tendons to phalanges of four lateral toes

action: Extends four lateral toes; dorsiflexes and everts foot

extensor hallucis longus

anterior compartment

origin: Middle fibula and interosseous membrane

insertion: Distal phalanx of great toe

action: Extends great toe; dorsiflexes and inverts foot

tibialis anterior

anterior compartment

origin: Tibia and interosseous membrane

insertion: Medial cuneiform and first metatarsal bone

action: Dorsiflexes and inverts foot

fibularis tersius

anterior compartment

origin: Fibula and interosseous membrane

insertion: Fifth metatarsal bone

action: Dorsiflexes and everts foot

Gastrocnemius

superficial posterior compartment

origin: Medial and lateral condyles of femur

insertion: Through calcaneal (Achilles) tendon to calcaneus

action: Plantar flexes foot; flexes leg

soleus

superficial posterior compartment

origin: Fibula and tibia

insertion: Through calcaneal tendon to calcaneus

action: Plantar flexes foot

flexor digitorum longus

deep posterior compartment

origin: Tibia

insertion: Four tendons to distal phalanges of four lateral toes

action: Flexes four lateral toes; plantar flexes and inverts foot

Flexor hallucis longus

deep posterior compartment

origin: Fibula

insertion: Distal phalanx of great toe

action: Flexes great toe; plantar flexes and inverts foot

Tibialis posterior

deep posterior compartment

origin: Tibia, interosseous membrane, and fibula

insertion: Navicular, cuneiforms, cuboid, and second through fourth metatarsal bones

action: Plantar flexes and inverts foot

peroneus Fibularis brevis

lateral compartment

origin: Fibula

insertion: Fifth metatarsal bone

action: Everts and plantar flexes foot