Muscle Actions

Epicranius

Raises eyebrows and wrinkles forehead

Orbicularis oculi

Closes eye

Zygomaticus major/minor

Elevates corners of the mouth

Risouris

Pulls lips laterally

Orbicularis oris

Closes mouth and protrudes lips

Mentalis

Wrinkles chin and protrudes lower lip

Buccinator

Compresses cheeks (kissing)

Platysma

Tenses fascia of the neck and depresses mandible

Masseter

Elevates mandible/jaw closure, prime mover of mastication (chewing)

Temporalis

Synergist to masseter, elevates mandible/closes jaw

Digastric

Depresses mandible/opens mouth, elevates larynx

Sternohyoid

Depresses hyoid and larynx

Sternothyroid

Pulls larynx and hyoid bone inferiorly

Omohyoid

Depresses and retracts hyoid bone

Sternocleidomastoid

Laterally rotates and flexes the head

Scalenes

Elevates the first two ribs

Splenius

Extends head

Illiocostalis/longissimiss

Extend and laterally flex vertebral column (2 muscles)

Spinalis

Extends vertebral column

External intercostals

Synergist to diaphragm, elevates rib cage for inspiration

Internal intercostals

Antagonist to diaphragm and external intercostals, depresses rib cage for expiration

Diaphragm

Prime mover of inspiration, expands ribcage

Rectus femoris

Ab muscles, flex and rotate lumbar region of spine

External oblique

Fibers run DOWN, compress abdomen, flex vertebral column, laterally rotate and flex trunk

Internal oblique

Fibers run UP, compresses abdomen, flex vertebral column, laterally rotates and flexes the trunk

Transverse abdominus

Deepest abdominal muscle, compresses abdomen

Pectoralis minor

Moves scapula forward and down

Serratus atnerior

Upward rotation of the scapula (throwing muscle)

Subclavius

Stabilizes and depresses the pectoral girdle

Trapezius

Stabilizes, retracts, raises, depresses, and rotates scapula

Levator scapulae

Elevates scapula

Rhomboid major/minor

Stabilizes, ADDucts, and rotates scapula downwards

Pectoralis major

Prime mover of arm flexion, ADDucts and medially rotates arm

Prime mover of arm extension, ADDucts and medially rotates arm at the shoulder

Deltoid

Prime mover of arm ABDuction

Teres major

Extends, medially rotates, and ADDucts humerus

Subscapularis

Medially rotates shoulder

Supraspinatus

ABDuction of shoulder

Infraspinatus/teres minor

Laterally rotates shoulder (2 muscles)

Coracobrachialis

Synergist to pectoralis major, ADDucts and flexes arm

Triceps brachii

Prime mover of elbow extension

Aconeus

Synergist to triceps brachii, extends elbow

Biceps brachii

Elbow and shoulder flexion, also supinates forearms

Brachialis

Forearm flexor

Brachioradialis

Synergist to brachialis, forearm flexor

Pronator teres

Pronates arm and forearm

Flexor carpi radialis

Flexes and ABDucts wrist

Palmaris longus

Flexes wrist

Flexor digitorum superficialis

Flexes middle and proximal phalanges

Flexor pollicis longus

Flexes thumb

Flexor digitorum profundus

Flexes distal phalanges

Extensor carpi radialis longus

Extends wrist

Extensor carpi radialis brevis

Extends and ABDucts wrist

Extensor digitorum

Extends phalanges

Extensor carpi ulnaris

Extends and ADDucts wrist

Abductor pollicis longus

ABDucts thumb and extends wrist

Extensor indicis

Extends index finger

Illiacus

Prime mover of thigh and trunk flexion

Psoas major

Prime mover of thigh and trunk flexion, laterally flexes vertebral column

Sartorius

Flexes thigh and knee, ABDucts and laterally rotates the thigh (criss-cross)

Adductor longus/pectineus

ADDucts, flexes, and medially rotates thigh (2 muscles)

Adductor brevis

ADDucts and medially rotates thigh

Adductor magnus

Synergist to hamstrings for extension, ADDucts hip and medially rotates thigh

Gracilis

ADDucts and medially rotates thigh, flexes and medially rotates leg (walking)

Rectus femoris

Extends knee and weakly flexes thigh

Vastus lateralis

Extends and stabilizes knee

Vastus intermedius/medialis

Extends knee (2 muscles)

Tensor fasciae latae

Steadies trunk and thigh, tenses IT band/tract

Gluteus maximus

Thigh extensor, lateral rotator, extends knee, and ABDucts hip

Gluteus medius/minimus

ABDucts and medially rotates thigh (2 muscle)

Piriformis, gamellus superior/inferior, obturator internus/externus, and quadratis femoris

Laterally rotate and ABDuct the hip (6 muscles)

Biceps femoris, semitendinosus, and semimembranosus

Extend thigh and flex knee, hamstrings (3 muscles)

Tibialis anterior

Prime mover of dorsiflexion

Extensor digitorum longus

Prime mover of toe extension

Extensor hallucis longus

Extends big toe

Gastrocnemius/soleus

Plantar flex the foot (2 muscles)

Plantaris

Knee and plantar flexion

Popliteus

Flexes and rotates leg medially

Flexor digitorum longus

Plantar flexes and inverts foot, flexes toes

Flexor hallucis longus

Plantar flexes and inverts foot, flexes big toe

Tibialis posterior

Prime mover of foot inversion