muscles and Actions

orbicularis oculi

Closes eyelids; used in blinking, winking, and squinting

orbicularis oris

closes and protrudes lips

Omohyoid

depresses hyoid bone

pectoralis minor muscle

protracts and depresses scapula

Coracobrachialis

Flexes and adducts the humerus

Deltoid

abducts, flexes, and extends arm

Brachialis

flexes elbow

flexor digitorum profundus

flexes distal phalanges

rectus abdominis

flexes vertebral column

internal oblique

flexes and rotates vertebral column

Temporalis

elevates and retracts mandible

Masseter

elevates mandible

Sternocleidomastoid

Contraction of one side: laterally flexes neck, rotates head to opposite side; Contraction of both sides together: flexes neck

Trapezius

Elevates, depresses, retracts, and rotates the scapula

pectoralis major

all fibers Adduct, medially rotates, upper fibers flex & horizontally adduct G/H joint, lower fibers extend

serratus anterior

pulls scapula anteriorly and downward

biceps brachii

flexes shoulder, Flexes and supinates forearm

external oblique

Compresses abdomen; laterally flexes and rotates vertebral column

Brachioradialis

flexes elbow

flexor carpi ulnaris

flexes wrist and adducts hand

Pectineus

adducts, flexes, and medially rotates thigh

Sartorius

Flexes, abducts, and laterally rotates thigh at the hip; flexes knee

Gracilis

adducts thigh, flexes and medially rotates leg

rectus femoris

extends knee and flexes thigh at hip

vastus lateralis

extends leg

vastus medialis

extends leg

Gastrocnemius

flex the knee, plantar flexes foot

fibularis longus

plantar flexes and everts foot

fibularis brevis

plantar flexes and everts foot

tibialis anterior

dorsiflexes and inverts foot

extensor digitorum brevis

extends toes 2-4

adductor longus

adducts, flexes, and medially rotates thigh

vastus intermedius

extends leg

extensor digitorum longus

extends toes and dorsiflexes foot

Soleus

plantar flexes foot

Supraspinatus

one of the "rotator cuff" muscles; Abducts arm; stabilizes the head of the humerus

Rhomboid minor and major

scapula retraction

Infraspinatus

Laterally rotates shoulder; stabilizes the head of the humerus

teres major

extends, adducts, and medially rotates arm

teres minor

rotates arm laterally; adducts and stabilizes humerus

triceps brachii

extends arm and forearm

gluteus medius

abducts and medially rotates thigh

Piriformis

laterally rotates and abducts thigh

quadratus femoris

laterally rotates thigh

gluteus maximus

extends, laterally rotates, abducts, and adducts hip

Semimembranosus

Flexes leg at the knee and extends thigh at the hip

biceps femoris

extends thigh and flexes leg

Plantaris

plantar flexion

splenius capitis

rotates head, bends head to one side, or extends neck

latissimus dorsi

Extends, adducts, and medially rotates the arm; draws the shoulder downward and backward

extensor carpi ulnaris

extends and adducts wrist

extensor digitorum

Extends fingers and the wrist

occipitalis

pulls scalp posteriorly

Platysma

tenses skin of neck

abductor hallucis

abducts great toe

Frontalis

raises eyebrows, wrinkles forehead

tensor fasciae latae

Abducts, flexes, and rotates the thigh medially

adductor magnus

adducts thigh, extends thigh at hip

Semitendinosus

Flexes leg at the knee and extends thigh at the hip; belongs to the hamstring group

Frontalis

superficial to frontal bone

Action of frontalis

raises the eyebrows/wrinkles the brow

Orbuclaris Oris

Muscles near the mouth

Action of Orbicularis Oculi

closes eye as in blinking

Zygomaticus

extends from cheekbones to corners of the mouth

Action of zygomaticus

raises lateral corners of the mouth when smiling

draws angle of mouth upward and laterally

Masseter

Action of masseter

elevataion and protusion the mandible

Temporalis

Action of temporalis

elevatation and retraction of the mandible

Sternocleidomastoid

Action of sternocleidomastoid

flexes and/or laterally rotates the head

Diaphragm

Action of diaphragm

inspiration - contracts to increase intra-abdominal pressure to force air into lungs

External oblique

fibers run down toward midline

Action of of external oblique

flex vertebral column, rotation if one side

Internal oblique

fibers run up toward midline

Action of internal oblique

flex vertebral column, rotation if one side

Rectus abdominis

fibers run up and down

Action of rectus abdominis

flex and rotate lumbar region

Pectoralis major

large chest muscle

Action of pectoralis major

flexes the humerus

extends the humorus

protracts and rotates scapula downward

Serratus anterior

"fingers"

Action of serratus anterior

rotates scapula upward

Trapezius

broad back muscle

Action of trapezius

stabilizes, elevates, retracts, and rotates scapula, extends head

Rhomboids (major and minor)

Action of rhomboids

stabilize scapula

Deltoid

shoulder muscle

Action of deltoid

shoulder abduction, flexion and extension

Latissimus dorsi

broad back muscle

Action of latissimus dorsi

Adducts, extends and internally rotates the arm when the insertion is moved towards the origin.

rotator of the trunk

Teres major

Action of teres major

extends, medially rotates, and adducts the arm

Infraspinatus

rotator cuff muscle

Action of infraspinatus

laterally rotates arm

Teres minor

rotator cuff muscle

Action of teres minor

laterally rotates arm

Triceps brachii

posterior brachial region

Action of triceps brachii

Extends forearm, long head extends, adducts arm, Extends shoulder

Biceps brachii

anterior brachial region