• Ch. 10: The Muscular System:• Three things that a muscle will be assigned to

perform:

1.) Agonist: Prime mover, main muscle or muscles doing the intended job or performance.

2.) Antagonists: Muscle or a group of muscles that is associated with agonist in whatever movement the agonist does the antagonist does the opposite of.

- If the agonist is flexing the antagonist is extending.

3.) Synergist: Muscle or muscles that aid in the movement of either the agonist or the antagonist muscles.

• The Muscular System:• Just like the skeletal system, the muscular system is

divided into two groups:– Axial muscle group: Head, thoracic, spine.– Appendicular muscle group: Arms, hands, legs, feet.

• The Muscular System:• The purpose of the muscular system is to

do work.• In order to complete this task the muscles

attaching to the bones allows them to act as levers.

• Three different types of levers.– 1st class lever– 2nd class lever– 3rd class lever

• The Muscular System:• Levers

– 1st class lever: fulcrum or pivot point is in the middle, resistance on one side and the effort is on the other side.

- tilting your chin back, spine is the pivot, resistance is your chin, effort is the

muscles attached to the base of the head.Load

Fulcrum

Effort

EffortLoad

Fulcrum

EffortLoad

Fulcrum

• The Muscular System:• Levers

– 2nd class lever: fulcrum is at one end, the load is in the middle, effort is at the other end.

- Lifting your heel off the ground, pivot is your toes, resistance is the heel, effort is your calf muscles.

Fulcrum Effort

Load

Fulcrum

Load

Effort

• The Muscular System:• Levers

– 3rd class lever: fulcrum is at one end, effort is in the middle, resistance is at the other end.

- Doing a bicep curl, pivot is your elbow, resistance is in your hand, effort is coming from your forearm (distal).

Fulcrum

EffortLoad

FulcrumLoad

Effort

• The Muscular System:• Frontalis:• O: Galea aponeurotica

(sheath on the mid head)• I: Above the eyebrow• F: Raise eyebrows

• The Muscular System:• Occipitalis:• O: External protuberance

of the occipital bone• I: Galea aponeurotica• F: Retract scalp

• The Muscular System:• Temporalis:• O: Temporal lines of the

skull (suture sites)• I: Coronoid process• F: Elevate mandible

• The Muscular System:• Orbicularis oculi:• O: Medial portion of the

eye orbit• I: Skin around the eyelid• F: Close and open eye

• The Muscular System:• Zygomaticus:• O: Zygomatic bone• I: Skin on the corner of

the mouth• F: Draw the corners of

the mouth up and back

• The Muscular System:• Masseter:• O: Zygomatic arch• I: Lateral surface of the

mandible• F: Elevate mandible

• The Muscular System:• Buccinator:• O: Distal portions of the

maxilla and mandible• I: Orbicularis oris• F: Compress checks

• The Muscular System:• Orbicularis oris:• O: Maxilla and mandible• I: Lips• F: Compress lips

• The Muscular System:

• Sternocleidomastoid:• O: Superior aspect of

sternum and clavicle• I: Mastoid process• F: flex the neck, allows

the head to pivot

• The Muscular System:• External intercostals

(outside of the ribcage):• O: Inferior border of each

rib above• I: Superior border of each

rib below• F: Elevate ribs, protect

internal organs

• The Muscular System:• Internal intercostals

(inside the ribcage):• O: Superior border of the

rib below• I: Inferior border of the rib

above• F: Depress rib

• The Muscular System:• External oblique (outside

ab muscles):• O: Lower portion of the

eighth rib• I: Iliac crest• F: Compress abdomen

• The Muscular System:• Internal oblique (inside

body cavity ab muscle):• O: Iliac crest• I: Lower portion of the

ribs, xiphoid process• F: Compress the

abdomen

• The Muscular System:• Transverse abdominous

(inner most ab muscle):• O: Cartilage of lower ribs,

iliac crest• I: Pubis• F: Compress abdomen

• The Muscular System:• Rectus abdominous (front

portion of abs):• O: Superior aspect of the

pubis symphysis• I: Inferior surface of ribs

5-7, xiphoid process• F: Depress ribs

• The Muscular System:• Serratus anterior:• O: Lateral side of ribs one

through nine• I: Anterior surface of

scapula, medial border• F: protract scapula

against the chest wall, boxers muscle

• The Muscular System:• Pectoralis Major:• Fan shaped muscle that is

superficial on the anterior side of the thoracic cavity

• O: Sternum (body), clavicle

• I: Greater tubercle of the humerus

• F: Adduct of the arm, helps with throwing and flexion of the arm

• The Muscular System:• Pectoralis Minor:• Lies deep to the

pectoralis major.• O: Ribs 3-5

• I: Coracoid process of the scapula

• F: Raise ribs 3-5, depress glenoid cavity

• The Muscular System:• Deltoid:• Thick three bodied

muscles• O: Clavicle, acromion

spine of the scapula (posterior side)

• I: Proximal head of the humerus

• F: Abduction, forward flexion, and backward flexion

• The Muscular System:• Latissimus dorsi (Lats):• Triangular muscle in the

lower back• O: Spinous process of the

lower thoracic and lumbar back

• I: Between greater and lesser tubercle of humerus

• F: Arm extension and adduction

• The Muscular System:• Trapezius• Upper back muscles• O: External protuberance

of the occipital bone, C7 and all spinous process of thoracic vertebrae.

• I: Acromion spine of scapula, lateral clavicle

• F: Raise scapula, stabilize head

• The Muscular System:• Levator scapulae:• Deep to the trapezius• O: Transverse process of

C1 – C4• I: Upper portion of the

medial border, above the scapula spine

• F: Elevate and adduct scapula

• The Muscular System:• Rhomboids:• Two muscles (minor and

major) both lie deep to the trapezius

• O: Spinous process of C7 – T5

• I: Medial Border of scapula

• F: Retract scapula, helps with posture

• The Muscular System:• Rotator cuff:• Subscapularis:• Anterior muscle under the

scapula• O: Ventral (front) surface

of scapula, subscapularis fossa

• I: Lesser tubercle of humerus

• F: Assists in arm movement

• The Muscular System:• Rotator cuff:• Supraspinatus:• Sits above the spine of

the scapula• O: Medial border,

superior aspect of the scapula, supraspinous fossa

• I: Greater tubercle of humerus

• F: Stabilize the shoulder

• The Muscular System:• Rotator cuff:• Infraspinatus:• Sits below the spine of

the scapula• O: Medial border, inferior

aspect of the scapula, infraspinous fossa

• I: Greater tubercle of the humerus

• F: Stabilize humerus and aid in ROM

• The Muscular System:• Rotator cuff:• Teres minor:• Small round muscle• O: Lateral, dorsal border

of scapula• I: Greater tubercle of

humerus• F: Stabilize humerus and

aid in ROM

• The Muscular System:• Rotator cuff:• Teres major:• Thick rounded, inferior to

teres minor• O: posterior surface of

scapula• I: groove of humerus• F: adducts humerus,

external rotation of arm

• The Muscular System:• Biceps brachii:• Anterior surface of upper

arm• Composed of two heads

(Biceps)• O: Coracoid process• I: Radial tuberosity• F: Flexion of the arm

(flexion of the radius)

• The Muscular System:• Brachialis:• Lies underneath the

biceps brachii• O: Distal half of the

humerus• I: Coronoid process of the

ulna (anterior elbow)• F: Flexion of the arm

(flexion of the ulna)

• The Muscular System:• Brachioradialis:• Superficial muscle on the

lateral side of the arm• O: Distal end of the

humerus• I: Styloid process of

radius• F: Synergist muscle for

flexion of the arm

• The Muscular System:• Triceps brachii:• Posterior surface of the

upper arm• Composed of three heads

(Triceps)• O: Superior, lateral

border of the scapula• I: Olecranon process• F: Extension of the arm

• The Muscular System:• Flexor digitorium

superficialis:• Anterior surface of the

lower arm• Four different muscles

(one for each digit)• O: Medial epicondyle of

the humerus• I: Middle phalanges of

digits 2-5• F: Flex digits (curl)

• The Muscular System:• Flexor pollicis longus:• Anterior surface of the

lower arm• One muscle• O: Anterior surface of the

distal radius• I: Distal phalanges of the

thumb, anterior side• F: Flex the thumb

• The Muscular System:• Flexor pollicis brevis:• Anterior surface of the lower arm• Synergist for the flexor pollicis

longus• One muscle• O: Trapezium• I: Proximal phalange of the thumb• F: Flex the thumb

• The Muscular System:• Extensor digitorium

superficialis• Posterior surface of the

lower arm• Four muscles, one for

each digit• O: Lateral epicondyle of

humerus• I: Distal phalanges of

digits 2-5• F: Extend each digit

• The Muscular System:• Supinator:• Anterior surface of the

forearm. Lies deep to the flexor digit.

• O: Lateral epicondyle of the humerus

• I: upper 1/3 of the radius• F: Supination of the

forearm into the ACP

• The Muscular System:• Pronator teres:• Located on the anterior

surface of the forearm. Lies deep to the flexor digit.

• O: Medial epicondyle of the humerus

• I: Lateral side of the shaft of the radius

• F: Pronate the forearm out of the ACP

• The Muscular System:• Flexor carpi radialis:• Located on the anterior

surface of the forearm. Superficial to the flex. digit.

• O: Medial epicondyle of the humerus

• I: 2nd and 3rd metacarpals• F: flex wrist

• The Muscular System:• Flexor carpi ulnaris:• Located on the anterior

surface of the forearm. Superficial to the flex. digit.

• O: medial epicondyle of the humerus, medial side of the olecranon process

• I: pisiform, hamate, 5th metacarpal

• F: flex the wrist

• The Muscular System:• Extensor carpi radialis

longus:• Located on the posterior

surface of the forearm.• O: Lateral surface of the

humerus superior to the condyle

• I: 2nd metacarpal• F: Extend the wrist

• The Muscular System:• Extensor carpi ulnaris:• Located posterior surface

of the forearm• O: Lateral epicondyle of

the humerus, shaft of the ulna

• I: 5th metacarpal• F: Extends the wrist

• The Muscular System:• Extensor pollicus longus:• Posterior surface of lower

arm• One muscle• O: Posterior distal surface

of radius and ulna• I: Distal phalange of

thumb, posterior side• F: Extend thumb

• The Muscular System:• Thigh and Pelvis • Ilopsoas:• Aids in ROM (flexion).• O: Iliac crest, lateral

surface of the sacrum• I: Lesser trochanter on

the femur• F: Flex of the hip when

trunk is in a solid position.

• The Muscular System:• Thigh and Pelvis • Adductor longus:• Main adductor muscle• Covers the middle portion

of the adductor magnus• O: Pubis synthesis• I: Medial shaft of the

femur• F: Flex the leg, laterally

rotates leg, adduction

• The Muscular System:• Thigh and Pelvis• Adductor magnus:• Synergist to the adductor

longus• Large triangular with a broad

insertion point• Lies deep to the adductor

longus• O: Ischial tuberosity• I: Medial side of the femur

(proximal head, shaft, distal head)

• F: Aid in adduction of leg

• The Muscular System:• Thigh and Pelvis• Adductor brevis:• Synergist for the add. Longus• Lies deep to the add. Longus• Superficial to the add. Magnus• O: Ischium• I: Above the add. Longus on

the shaft of the femur• F: Aid in adduction

• The Muscular System:• Thigh and Pelvis• Gracilis:• Medial portion of the thigh• Groin muscle• O: Body of the pubis

bone• I: Medial surface of the

proximal head of the tibia• F: Adduct thigh, flex hip,

main walking muscle

• The Muscular System:• Thigh and Pelvis• Sartorius:• Longest muscle in the

body• O: Anterior portion of the

iliac crest• I: Medial aspect of the

proximal head of the tibia• F: Flex knee, laterally

rotate knee

• The Muscular System:• Thigh and Pelvis• Tensor fasciae latae:• Wide band of muscle

located on the medial side of the thigh

• O: Anterior aspect of the iliac crest

• I: Lateral aspect of the proximal head of the tibia

• F: Flex and medially rotate the knee

• The Muscular System:• Thigh and Pelvis• Quadriceps• Located on the anterior side of the leg.• Made up of four muscles

– Rectus femoris – Vastus lateralis– Vastus medialis– Vastus intermedius

• Extends knee

• The Muscular System:• Thigh and Pelvis• Rectus femoris:• Superficial muscle in the

thigh• Largest quad muscle• O: Anterior and inferior

iliac crest• I: Superior border of the

patella• F: Extend knee, flex the

thigh, stabilize patella

• The Muscular System:• Thigh and Pelvis• Vastus lateralis:• Lateral side of the thigh• Synergist to the rectus

femoris• O: Greater trochanter of

the femur• I: Lateral border of the

patella• F: Extend knee, stabilize

patella

• The Muscular System:• Thigh and Pelvis• Vastus medialis:• Medial side of the thigh• Synergist for the rectus

femoris• O: Proximal head of the

femur• I: Medial surface of the

patella • F: Extend knee, stabilize

patella

• The Muscular System:• Thigh and Pelvis• Vastus intermedius:• Lies deep to the rectus

femoris• O: Proximal head of the

femur• I: Superior border of he

patella (underneath the rectus femoris insertion)

• F: Extend knee, stabilize patella

• The Muscular System:• Thigh and Pelvis• Tibialis anterior:• Anterior portion of the leg• Next to the tibia crest• O: Lateral condyle of the

tibia• I: 1st cuneiform (medial)

and the first metatarsal• F: Dorsiflexion

• The Muscular System:• Thigh and Pelvis• Extensor digitorium

longus:• Lateral side of the lower

leg• O: Lateral condyle of the

tibia and the majority (3/4) of the proximal fibula

• I: Middle and distal phalanges of the digits 2-5

• F: Extend toes

• The Muscular System:• Thigh and Pelvis• Extensor hallucis longus:• Medial side of the lower

leg• Great toe (big toe)• O: Medial fibula shaft• I: Distal phalange of the

great toe• F: Extend great toe

• The Muscular System:• Thigh and Pelvis• Hamstrings:• Located on the posterior side of the thigh• Flexes the knee• Made up of three muscles:

– Semimembranous– Biceps femoris– Semitendinous

• The Muscular System:• Thigh and Pelvis• Semimembranous:• Lies on the medial portion

of the thigh• Lies deep to the

semitendinous• Larger than the

semitendinous• O: Ischium• I: Medial condyle of the

tibia• F: Flex knee

• The Muscular System:• Thigh and Pelvis• Semitendinous:• Lies on the medial portion

of the thigh• Superficial to the

semimembranous• O: Ischium• I: Medial, superior tibial

shaft• F: Flex knee

• The Muscular System:• Thigh and Pelvis• Biceps femoris:• Lies on the lateral portion

of the thigh• O: Ischium and the

proximal head of the femur

• I: Head of the fibula and lateral condyle of the tibia

• F: Flex knee

• The Muscular System:• Thigh and Pelvis• Buttock muscles:• Cushioning and protection for the pelvic girdle.• Three muscles that make up the buttock

muscles.– Gluteus maximus– Gluteus medius– Gluteus minimus

• The Muscular System:

• Thigh and Pelvis• Gluteus maximus:• Main bulk of the

buttocks, superficial• O: Ilium, sacrum,

coccyx• I: Proximal head of

the femur• F: Extend leg when

walking and climbing

• The Muscular System:

• Thigh and Pelvis• Gluteus medius:• Lies deep to the

gluteus maximus• O: Ilium• I: Greater trochanter

of femur via a small tendon

• F: Stabilize pelvis when walking

• The Muscular System:• Thigh and Pelvis• Gluteus minimus:• Lies deep to the gluteus

medius• Main synergist buttock

muscle• O: Ilium• I: Anterior border of the

greater trochanter of the femur

• F: Help stabilize the pelvis

• The Muscular System:• Thigh and Pelvis• Gastronemius:• Superficial muscle• O: Medial and lateral

condyle of the femur• I: Calcaneus• F: Plantar flexion

• The Muscular System:• Thigh and Pelvis• Soleus:• Lies deep to the

gastronemius• Synergist for the

gastronemius• O: Proximal head of the

tibia and fibula• I: Calcaneus (underneath

the insertion of the gastronemius)

• F: Plantar flexion

• The Muscular System:

• Thigh and Pelvis• Flexor digitorium

longus:• Medial portion of the

lower leg• O: Medial condyle of

the tibia (posterior)• I: Distal phalanges of

digits 2-5• F: Flex toes

• The Muscular System:• Thigh and Pelvis• Flexor hallucis longus:• Great toe (big toe)• Medial portion of the

lower leg• O: Middle of the fibula

shaft• I: Distal phalange of the

great toe• F: Flex the great toe