Muscles- Actions, Origins And Insertions

Elevates eyebrows, wrinkles skin of forehead

Forms floor of thoracic cavity, causes inspiration- when relaxed, air is forced out of lungs

Group of muscles that extend spine- holds body in upright posture

Compresses abdomen but does not flex lumbar spine

Compresses abdomen and flexes lower spine

Compresses abdomen and flexes lumbar spine

Elevates ribs, expanding rib cage during inspiration

Depresses ribs, compresses rib cage during forced expiration

Closing opening to anus

Group of muscles function together and tense floor of pelvis to support pelvic organs

Adults scapula, rotates it downward and pulls against ribs

Origin- ribs 3 to 5

Insertion- coracoid process of scapula

Abducts scapula and rotates upward (lifting arms)

Adducts scapula and rotates up (lifting arms)

Adducts, elevates and rotates scapula downward

Adducts, flexes and medially rotates humerus at shoulder

Origin- clavicle, cartilage of ribs 2 to 6 and sternum

Insertion- greater tubercle of humerus

Adducts, extends and medically rotates humerus at shoulder

Abducts, flexes, extends and rotates humerus at shoulder

Origin- clavicle, acromial process and spine of scapula

Insertion- deltoid tuberosity of humerus

Assists deltoid in abducting humerus at shoulder

Laterally rotates humerus at shoulder

Laterally rotates and extends humerus at shoulder

Medically rotates arm at shoulder

Flexes forearm at elbow and humerus at shoulder

Origin- scapula

Insertion- radial tuberosity of radius

Extends forearm at elbow and extends humerus at shoulder

Origin- scapula and humerus

Insertion- olecranon process of ulna

Flexes and laterally rotates femur at hip and flexes trunk at hip as when sitting up from supine position

Extends and laterally rotates femur at hip

Origin- iliac crest and sacrum

Insertion- linea aspera

Abducts and medially rotates femur at hip

Adducts and flexes femur at hip

Origin: pubis bone

Insertion- linea aspera of femur

Abducts and flexes femur at hip

Flexes femur at hip, flexes and laterally rotates leg at knee (crossing legs)

Origin- anterior illiac spine

Insertion- tibia

Together flex leg at knee and extend femur at hip

Plantar flexes foot at ankle and flexes leg at knee

Origin- medial and lateral condyles of femur

Insertion- calcaneous via calcaneal tendon (Achilles tendon)

Dorsiflexes & inverts foot at ankle

Plantar flexes and everts foot at ankle

Extends leg at knee when working with quadriceps femoris- when alone flexes femur at hip

Extends leg at knee when working with quadriceps femoris

Extends leg at knee when working with quadriceps femoris

Extends leg at knee when working with quadriceps femoris

Flexes lumbar spine (sit ups) and go presses abdomen for pooping, peeing, and childbirth

Origin- superior ramus of pubic bones and pubic symphysis

Insertion- xiphoid process and inferior surfaces of costal cartilage

Together flex cervical spine (head to chest) if only one contracts, rotates head and neck to opposite side

Origin- sternum and clavicle

Insertion- mastoid process of temporal bone

Elevates mandible (chewing)

Origin- maxilla and zygomatic arch

Insertion- mandible

Elevates and retracts mandible (chewing)

Origin- temporal bone

Insertion- coronoid process of mandible

Depresses angle of mouth (frowning) and depresses mandible

Draws cheeks in against teeth (sucking, blowing, whistling)

Elevates angle of mouth upward and laterally (smiling)

Origin- zygomatic bone

Insertion- skin at angle of mouth

Closed lips

Closes eyelids