Gross Anatomy of the Muscular System

ACTIONS

Frontalis

Raises eyebrows

Occipitalis

Retracts scalp

Temporalis

Closes mandible

Masseter

Closes mandible

Orbicularis oculi

Closes eyelid

Orbicularis oris

Closes lips

Buccinator

Compresses cheeks

Zygomaticus

Elevates corners of mouth

Sternocleidomastoid

Abducts, rotates, flexes head

External oblique

Compresses abdomen, laterally rotates waist

Internal oblique

Compresses abdomen, laterally rotates waist

Transverse abdominis

Compresses abdomen, laterally rotates waist

Rectus abdominis

Flexes spine, compresses abdomen

Serratus anterior

Abducts scapula

External intercostal

Elevates ribs

Internal intercostal

Depresses ribs

Diaphragm

Inspiration

Trapezius

Extends head, rotates scapula

Deltoid

Abducts arms

Pectoralis major

Flexes, adducts, rotates humerus

Latissimus dorsi

Extends, adducts, rotates arm

Supraspinatus

Abducts arm, stabilizes shoulder

Infraspinatus

Laterally rotates arm

Teres major

Extends, adducts, rotates arms

Biceps brachii

Flexes, supinates forearm

Triceps brachii

Extends forearm

Brachialis

Flexes forearm

Bracioradialis

Flexes forearm

Pronator teres

Pronates forearm

Palmaris longus

Anchors skins and fascia of palm

Flexor carpi radialis

Flexes, abducts wrist

Flexor carpi ulnaris

Flexes, adducts wrist

Thenar

Flexes, abducts, and opposes thumbs

Extensor carpi radialis

Extends, abducts wrists

Extensor carpi ulnaris

Extends, adducts wrist

Iliopsoas

Flexes thigh and lumbar vertebrae

Sartorius

Flexes and laterally rotates thigh flexes knee

Gracilis

Flexes and medially rotates leg

Pectineus

Adducts and flexes thigh

Adductor longus

Adducts, flexes, and medially rotates hip

Rectus femoris

Flexes thigh, extends leg

Vastus lateralis

Extends leg

Vastus medialis

Extends leg

Tensor fascia lata

Flexes thigh, extends and rotate knee

Gluteus maximus

Extends and abducts thigh

Gluteus medius

Abducts and medially rotates thigh

Biceps femoris

Extends thigh and flexes knee

Semitendinosus

Extends thigh and flexes knee

Semimembranosus

Extends thigh and flexes knee

Gastrocnemius

Flexes leg, plantar flexes foot

Soleus

Plantar flexes foot

Flexor digitorum longus

Flexes toes, plantar flexes foot, inverts foot

Tibialis anterior

Dorsiflexes, inverts foot

Extensor digitorum longus

Extends toes, dorsiflexes foot

Fibularis

Plantar flexes, everts foot