Muscles: Actions, Origins & Insertions

Frontalis

Action: raises eyebrows

Origin: galea aponeurotica

Insertion: eyebrow skin, bridge of nose

Masseter

Action: closes jaw; elevates mandible

Origin: zygomatic arch

Insertion: mandibular ramus

Occipitalis

Action: pulls scalp posteriorly

Origin: galea aponeurotica {thin sheet of connective tissue}

Insertion: galea aponeurotica {thin sheet of connective tissue}

Orbicularis Oculi

Action: closes, blinks and squints eyes

Origin: medial margin of orbit

Insertion: skin around eyelids

Orbicularis Oris

Action: closes mouth; kissing muscle

Origin: maxilla and mandible

Insertion: lips

Sternocleidomastoid

Action: rotates head, head flexion

Origin: clavicle and manubrium of sternum

Insertion: mastoid process of temporal bone

Sternohyoid

Action: depresses larynx and hyoid bone

Origin: clavicle and manubrium of sternum

Insertion: hyoid bone

External Intercostals

Action: elevates ribs

Origin: inferior border of each rib

Insertion: superior border of each rib

Temporalis

Action: closes jaw, elevates mandible

Origin: temporal bone

Insertion: coronoid process of mandible

Zygomaticus

Action: retracts and elevates upper lip

Origin: zygomatic bone

Insertion: skin on lateral sides of the mouth

Pectoralis Major

Action: flexion, adduction, and medial rotation at shoulder

Origin: ribs 2-6, sternum, and clavicle

Insertion: greater tubercle of humerus

Pectoralis Minor

Action: protracts scapula

Origin: ribs 3-5

Insertion: coracoid process of scapula

Rhomboid Major

Action: adducts scapula

Origin: spinous processes of vertebrae

Insertion: vertebral border of scapula

Serratus Anterior

Action: protracts scapula

Origin: ribs 1-8

Insertion: vertebral border of scapula

Trapezius

Action: extends neck; elevate or retract scapula

Origin: occipital bone and spinous processes of cervical and thoracic vertebrae

Insertion: clavicle and scapula

External Intercostals

Action: elevates ribs

Origin: inferior border of each rib

Insertion: superior border of each rib

Internal Intercostals

Action: depresses ribs

Origin: superior border of each rib

Insertion: inferior border of each rib

Deltoid

Action: abduction at shoulder

Origin: clavicle and scapula

Insertion: deltoid tuberosity of humerus

Latissimus Dorsi

Action: extension, adduction, and medial rotation at shoulder

Origin: spinous processes of inferior thoracic and all lumbar vertebrae

Insertion: intertubercular groove of humerus

Infraspinatus

Action: lateral rotation at shoulder

Origin: infraspinous fossa of scapula

Insertion: greater tubercle of humuerus

Supraspinatus

Action: Abduction at shoulder

Origin: supraspinous fossa of scapula

Insertion: greater tubercle of humerus

Teres Major

Action: extension, adduction, and medial rotation at shoulder

Origin: scapula

Insertion: intertubercular groove of humerus

Subscapularis

Action: medial rotation at shoulder

Origin: subscapular fossa of scapula

Insertion: lesser tubercle of humerus

Biceps Brachii

Action: flexion at elbow and shoulder, supination

Origin: coracoid process of scapula, and tubercle above the glenoid cavity of the scapula

Insertion: tuberosity of radius

Triceps Brachii

Action: extension at elbow

Origin: Three heads: scapula (1) and posterior humuerus (2)

Insertion: olecranon of ulna

Brachialis

Action: flexion at elbow

Origin: anterior distal humerus

Insertion: tuberosity of ulna

Brachioradialis

Action: flexion at elbow

Origin: ridge above lateral epicondyle of humerus

Insertion: styloid process of radius

Pronator Teres

Action: pronation

Origin: medial condyle of humerus and coronoid process of ulna

Insertion: radius

Flexor Carpi Radialis

Action: flexion and abduction at wrist

Origin: medial epicondyle of humerus

Insertion: base of 2nd and 3rd metacarpals

Palmaris Longus

Action: flexion at wrist

Origin: medial epicondyle of humerus

Insertion: palmar aponeurosis

Flexor Carpi Ulnaris

Action: flexion and adduction at wrist

Origin: medial epicondyle of humerus

Insertion: 5th metacarpal

Extensor Digitorum

Action: extension at finger joints and wrist

Origin: lateral epicondyle of humerus

Insertion: fingers 2-5

Extensor Carpi Ulnaris

Action: extension and adduction at wrist

Origin: lateral epicondyle of humerus

Insertion: base of 5th metacarpal

Extensor Carpi Radialis Longus

Action: extension and abduction at wrist

Origin: lateral supracondylar ridge of humerus

Insertion: base of 2nd metacarpal

diaphragm

Action: inspiration

Rectus Abdominis

Action: depresses ribs, flexes vertebral column, compresses abdomen

Origin: superior surface of pubis around symphysis

Insertion: xiphoid process of sternum

External Oblique

Action: compresses abdomen, depresses ribs, flexes or bends spine

Origin: ribs 5-12

Insertion: linea alba and pubis

Internal Oblique

Action: compresses abdomen, depresses ribs, flexes or bends spine

Origin: iliac crest

Insertion: inferior ribs, xiphoid process, linea alba

Transversus Abdominis

Action: compresses abdomen

Origin: cartilage of ribs 6-12, iliac crest

Insertion: linea alba and pubis

Gluteus Maximus

Action: extension and lateral rotation at hip

Origin: ilium, sacrum, coccyx

Insertion: iliotibial tract and gluteal tuberosity of femur

Gluteus Medius

Action: abduction and medial rotation at hip

Origin: iliac crest of ilium

Insertion: greater trochanter of femur

Sartorius

Action: flexion at knee, flexion and lateral rotation at hip

Origin: iliac spine of ilium

Insertion: medial surface of tibia near tibial tuberosity

Adductor Magnus/Longus/Brevis

Action: adduction, flexion, and medial rotation at hip

Origin: inferior ramus of pubis

Insertion: linea aspera of femur

Gracilis

Action: flexion at knee

Origin: inferior ramus of pubis

Insertion: medial surface of tibia

Iliopsoas (Iliacus)

Action: flexion at hip

Origin: iliac fossa of ilium

Insertion: lesser trochanter of femur

Iliopsoas (Psoas Major)

Action: flexion at hip

Origin: transverse processes of vertebra (T12-L5)

Insertion: lesser trochanter of femur

Biceps Femoris

Action: flexion at knee; extension and lateral rotation at hip

Origin: ischial tuberosity and linea aspera of femur

Insertion: head of fibula, lateral condyle of tibia

Semitendonosus

Action: flexion at knee; extension and medial rotation at hip

Origin: ischial tuberosity

Insertion: medial surface of tibia

Semimembranosus

Action: flexion at knee; extension and medial rotation at hip

Origin: ischial tuberosity

Insertion: medial condyle of tibia

Rectus Femoris

Action: extension ar knee; flexion at hip

Origin: iliac spine and acetabulum

Insertion: tibial tuberosity via patellar ligament

Vastus Lateralis

Action: extension at knee

Origin: greater trochanter of femur

Insertion: tibial tuberosity via patellar ligament

Vastus Medialis

Action: extension at knee

Origin: linea aspera of the femur

Insertion: tibial tuberosity via patellar ligament

Tibialis Anterior

Action: flexion (dorsiflexion) at ankle, inversion of foot

Origin: lateral condyle of tibia

Insertion: base of first metatarsal

Gastrocnemius

Action: extension (plantar flexion) at ankle, inversion of foot, flexion at knee

Origin: femoral condyles

Insertion: calcaneus bone

Soleus

Action: extension (plantar flexion) at ankle

Origin: head of fibula and shaft of tibia

Insertion: calcaneus bone

Fibularis Longus

Action: eversion of foot and extension (plantar flexion) at ankle

Origin: lateral condyle of tibia, head and shaft of fibula

Insertion: First metatarsal

Extensor Digitorum Longus

Action: Extension at joints of toes 2-5

Origin: lateral condyle of tibia, anterior surface of fibula

Insertion: toes 2-5