Muscle Actions

Epicranial Aponeurosis

Connects frontalis and occipitalis

frontalis

elevates eyebrows

occipitalis

elevate eyebrow (retracts scalp)

orbicularis oris

sphincter muscle that closes mouth & puckers lips

zygomaticus

Elevates corner of mouth

Buccinator

compresses cheek

orbicularis oculi

sphincter muscle that closes eyes

masseter

elevates and protracts mandible

sternocleidomastoid

As a pair, flex neck.

As antagonist, rotate head

upper trapezius

Elevates pectoral girdle

middle trapezius

pull scapulae medially / retracts scapula

lower trapezius

depresses pectoral girdle

latissimus dorsi

extends, adducts, and rotates arm

pectoralis major

adducts & medially rotates arm

serratus anterior

rotates scapula superiorly (stabilizes it)

pectoralis minor

abducts and depresses scapula

Synergist during forceful inhalation

diaphragm

contracts to flatten during inspiration

deltoid

abducts shoulder

rotates arms medially and laterally

biceps brachii

flexes elbow

supinates forearm

brachialis

flexes elbow

deep to biceps brachii

brachioradialis

flexes elbow

triceps brachii

extends elbow

adducts arm at shoulder (long head only)

rectus abdominis

compresses abdominal cavity and flexes trunk

external oblique

compresses abdominal cavity

Internal oblique

compresses abdominal cavity.

Transversus abdominis

compresses abdominal cavity

Deepest abdominal layer

gluteus maximus

extends hip/thigh

The largest muscle in the body

gluteus medius

abducts and rotates medially hip/thigh

hamstring

semitendinosus, semimembranosus, biceps femoris

quadricep

vastus intermedius, rectus femoris, vastus lateralis, vastus medialis.

tensor fascia lata

abducts and flexes hip/thigh

rotates thigh medially

gracilis

adducts hip/thigh

flexes knee

rectus femoris

extends knee

long-middle muscle of group

vastus lateralis

extends knee

lateral muscle of group

vastus medialis

extends knee

medial muscle of group

semitendinosus

flexes knee and extends hip/thigh

superficial medial portion muscle of group

semimembranosus

flexes knee and extends hip/thigh

deep medial muscle of group

biceps femoris

flexes knee and extends hip/thigh

lateral muscle of group

sartorius

flexes and rotates laterally hip/thigh

longest muscle in the body

AKA Taylor’s muscle

tibialis anterior

dorsiflexion

inversion of foot

extensor digitorum longus

extension of toes

dorsiflexion

gastrocnemius

plantar flexion

flexes knee

soleus

plantar flexion

deep to gastrocnemius

fibularis peroneus longus

plantar flexion

eversion of foot

calcaneal tendon

connects muscle of plantar flexion to calcaneus

AKA achilles