2020 Science Olympiad Major Skeletal Muscles

frontalis

raises eyebrows

Orbicularis oris

closes lips

Orbicularis oculi

closes eye

Occipitofrontalis

raises eyebrows

Zygomaticus major

smiling

Masseter

elevates mandible

Sternocleidomastoid

flexes neck; rotates head

Trapezius

Elevates, depresses, retracts, and rotates the scapula; rotates the arm

Buccinator

Used to suck in your cheeks

External Intercostals

elevates ribs (breathing)

Internal Intercostals

depresses ribs (breathing)

Transverse abdominis

compresses abdomen, protects spin

Infraspinatus

Laterally rotates shoulder

Rectus abdominis

flexes and rotates vertebral column

Serratus anterior

pulls scapula anteriorly and downward

Diaphragm

Large, flat muscle at the bottom of the chest cavity that helps with breathing

Pectoralis major

Adducts and flexes humerus

Latissimus dorsi

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

Deltoid

abducts arm

Teres major

extends, adducts, and medially rotates arm

Biceps brachii

flexes forearm

Triceps brachii

extends forearm

Brachialis

flexes forearm

Brachioradialis

flexes forearm

Palmaris longus

flexes wrist

Flexor carpi radialis

flexes wrist and abducts hand

Flexor digitorum superficialis

flexes wrist and middle phalanges of fingers 2-5

Extensor carpi radialis

Extends wrist and abducts hand

Extensor digitorum

extends fingers

Extensor digiti minimi

extends little finger

Extensor carpi ulnaris

extends and adducts wrist

Iliopsoas

flexes hip

Sartorius

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

Gluteus maximus

extends thigh

Gluteus medius

abducts and medially rotates thigh

Tensor fasciae latae

Abducts, flexes, and rotates the thigh medially

Adductor longus

adducts, flexes, and medially rotates thigh

Gracilis

adducts thigh, flexes and medially rotates leg

Semimembranosus

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

Semitendinosus

extends thigh and flexes leg

Biceps femoris

extends thigh and flexes leg

Rectus femoris

extends leg and flexes thigh

Vastus lateralis

extends knee

Vastus intermedium

extends knee

Vastus medialis

extends knee

Tibialis anterior

dorsiflexes and inverts foot

Gastrocnemius

calf muscle that flexes the knee and bends the foot downward

Soleus

plantar flexes foot

Peroneus longus

Muscle that covers the outer side of the calf; inverts the foot and turns it outward.

Peroneus brevis

Shorter of the two muscles responsible for rotating the foot down and out