Muscle Action

Front 1

Pulls scalp backward. Assists frontal belly to raise eyebrows and wrinkle forehead.

Back 1

Occipitalis

Front 2

Pulls scalp forward. Raises eyebrows and wrinkles skin of forehead horizontally.

Back 2

Frontalis

Front 3

Closes jaw. Clenches teeth. Assists in the side to side movement of mandible.

Back 3

Masseter & Temporalis

Front 4

Closes jaw. Clenches teeth. Assists in side to side movement of mandible.

Back 4

Temporalis

Front 5

Acting together: flex neck. Raise 1st rib during a strong inhalation

Individually: laterally flex and rotate neck

Back 5

Scalenus anterior, medius, posterior

Front 6

Contraction of both sides together: flexes neck and draws head forward. Raises sternum, and consequently ribs, superiorly during deep inhalation.

Contraction of one side: tilts head toward same side. Rotates head to face opposite side.

Back 6

Sternocleidomastoideus (SCM)

Front 7

Extends and laterally flexes vertebral column. Helps maintain correct curvature of spine in the erect and sitting positions. Steadies the vertebral column on the pelvis during walking.

Back 7

Erector spinae (sacroslinalis)

Iliocostalis

Longissimus

Spinalis

Front 8

Extends and rotates head. Helps maintain correct curvature of thoracic and cervical spine in the erect and sitting positions.

Back 8

Longissimus capitis

Front 9

Extends thoracic and cervical parts of vertebral column. Assists rotation of thoracic and cervical vertebrae.

Back 9

Semispinalis cervicis

Front 10

Most powerful extensor of the head. Assists in rotation of head.

Back 10

Semispinalis capitis

Front 11

Protects vertebral joints from movements produced by the more powerful superficial prime movers. Extension, lateral flexion, and rotation of vertebral column.

Back 11

Multifidus

Front 12

Rotate and assist in extension of vertebral column.

Back 12

Rotatores

Front 13

Acting together: extend head and neck

Individually: laterally flexes neck. Rotates face to same side as contracting muscle.

Back 13

Splenius capitis/ cervicis

Front 14

Compresses abdomen, helping to support abdominal viscera against pull of gravity. Contraction of one side alone bends trunk laterally to the side and rotates it to opposite side.

Back 14

External oblique

Front 15

Compresses abdomen, helping to support abdominal viscera against pull of gravity.

Back 15

Transversus abdominis

Front 16

Flexes lumbar spine. Depresses rib cage. Stabilizes pelvis during walking.

Back 16

Rectus abdominis

Front 17

Laterally flexes vertebral column. Fixes 12th rib during deep respiration. Helps extend lumbar part of vertebral column, and gives it lateral stability.

Back 17

Quadratus lumborum

Front 18

Main flexor of hip joint (flexes and laterally rotates thigh). Acting from its Insertion, flexes trunk.

Back 18

Iliopsoas (psoas major/ iliacus)

Front 19

Pulls shoulder girdle up (elevation). Helps prevent depression of shoulder girdle.

Retracts (adducts) scapula.

Depresses scapula, rotates scapula

Back 19

Trapezius

Front 20

Elevates scapula. Helps retract scapula. Helps bend neck laterally.

Back 20

Levator scapulae

Front 21

Retracts (adducts) scapula. Stabilizes scapula. Slightly assists in outer range of adduction of arm.

Back 21

Rhomboideus

Front 22

Rotates scapula for abduction and flexion of arm. Protracts scapula. Facilitates pushing movements.

Back 22

Serratus anterior

Front 23

Adducts and medially rotates humerus.

Flexes and medially rotates shoulder joint, and horizontally adducts humerus towards opposite shoulder.

Obliquely adducts humerus towards opposite hip.

Back 23

Pectoralis major

Front 24

Extends flexed arm. Adducts and medially rotates humerus. Assists in forced inspiration.

Back 24

Latissumus dorsi

Front 25

Flex and medially rotate humerus.

Abduct humerus.

Extend and laterally rotate humerus.

Back 25

Deltoideus

Front 26

Initiates process of abduction at shoulder joint.

Back 26

Supraspinatus

Front 27

Helps prevent posterior dislocation of shoulder joint. Laterally rotates humerus.

Back 27

Infraspinatus

Front 28

Helps prevent upward dislocation of shoulder joint. Laterally rotates humerus. Weakly adducts humerus.

Back 28

Teres minor

Front 29

Stabilizes glenohumeral joint, prevents head of humerus bring pulled upward by deltoid, biceps and long hear of triceps. Medially rotates humerus.

Back 29

Subscapularis

Front 30

Adducts humerus. Medially rotates humerus. Extends humerus from flexed position.

Back 30

Teres major

Front 31

Flexes elbow joint. Supinates forearm. Weakly flexes arm at shoulder joint.

Back 31

Biceps brachii

Front 32

Extends elbow joint. Adduct humerus and extend it from flexed position. Stabilizes shoulder joint.

Back 32

Triceps brachii

Front 33

Laterally rotates hip joint. May assist in abduction of hip joint.

Extend and laterally rotates hip joint. Extend trunk. Assists in adduction of hip joint.

Helps to stabilize knee in extension.

Back 33

Gluteus maximus

Front 34

Flexes, abducts, and medially rotates hip joint. Stabilizes knee joint. Redirects rotational forces produced by gluteus maximus.

Back 34

Tensor fasciae latae (tfl)

Front 35

Abducts hip joint. Medially rotate and may assist in flexion of hip joint. Slightly laterally rotate hip joint.

Back 35

Gluteus medius

Front 36

Abducts, medially rotates, and may assist in flexion of hip joint.

Back 36

Gluteus minimus

Front 37

Laterally rotates hip joint. Abducts thigh when hip is flexed. Helps hold head of femur in acetabulum.

Back 37

Piriformis

Front 38

Flex knee joint. Extend hip joint. Medially rotate lower leg when knee is flexed. Laterally rotates lower leg when knee is flexed.

Back 38

Hamstrings

Front 39

Adduct and laterally rotate hip joint. Flex extended femur and extend flexed femur.

Back 39

Adductors

Front 40

Adducts hip joint. Flexes hip joint.

Back 40

Pectineus

Front 41

Flexes hip joint. Laterally rotates and abducts hip joint. Flexes knee joint. Assists in medial rotation of tibia on femur after flexion.

Back 41

Sartorius

Front 42

Extends knee joint. Some parts flexes hip joint.

Back 42

Quadriceps

Front 43

Dorsiflexes ankle joint. Inverts foot.

Back 43

Tibialis anterior

Front 44

Extends toes at metatarsophalangeal joints. Assists extention of interphalangeal joints. Assists in dorsifexion of ankle joint and eversion of foot

Back 44

Extensor digitorum longus

Front 45

Extends all joints of great toe. Dorsiflexes ankle joint. Assists in inversion of foot.

Back 45

Extensor hallucis longus

Front 46

Plantar flexes foot at ankle joint. Assists in flexion of knee joint.

Back 46

Gastrocnemius

Front 47

Plantar flexes ankle joint. Helps maintain upright posture.

Back 47

Soleus