anatomy lab unit 8 the muscular system

agonists

prime moves, primarily responsible for producing a particular movement

antagonists

oppose, restrict, or reverse a movement

synergists

aid the action of agonists

fixators

specialized synergists that immobilize the origin of the agonist muscle so all tension is exerted at the insertion

muscle naming

direction of muscle fiber, relative size of muscle, location of muscle, number of origins, locaiton of muscle origin, shape, action

Epicranius frontalis

raise eyebrows

Epicranius occipitalis

pulls scalp posteriorly

orbicularis oculi

close eye/pull eyebrow down

orbicularis oris

close/protrude lips

masseter and temporalis

close jaw

platysma

open jaw/pull lower lip down

sternocleidomastoid

neck flexion/head rotation towards shoulder

Digastric anterior belly and Digastric posterior belly

open jaw/elevate hyoid bone

Mylohyoid

elevate hyoid bone & base of tongue

sternohyoid

depress larynx & hyoid bone

deltoid

abduct arm; flex/extend/rotate humerus

Pectoralis major

adduct/rotate medially arm; pulls chest upward (inhalation)

pectoralis minor

move scapula anterior/inferior; raise ribs (inhalation)

Serratus anterior

fixes scapula for arm abduction (essential for raising arm); pulls scapula anterior/inferior

rectus abdominis

flex vertebral column; depress ribs; compress abdomen (exhalation)

external oblique:

flex vertebral column; depress ribs; rotate trunk, compress abdomenm

internal oblique

flex vertebral column; depress ribs; rotate trunk, compress abdomen

transverse abdominis

compress abdomen

trapezius

extend head; adduct scapula & lateral clavicle

latissimus dorsi

extend, adduct & medial rotate arm

posterior compartment

triceps brachii: extend forearm

anterior compartment

biceps brachii: flex forearm

brachioradialis

brachialis

iliopsoas

flex trunk, thigh at hip

sartorius

flex, abduct, & laterally rotate thigh

Quadriceps femoris

extend lower leg at knee & flex thigh

tensor fasciae latae

flex, abduct, & medially rotate thigh

Quadriceps femoris

extend lower leg at knee & flex thigh

gluteus maximus

laterally rotate, abduct, & extend thigh

Gluteus medius

abduct & medially rotate thigh

biceps femoris

extend thigh; laterally rotate leg; flex knee

semitendinosus

extend thigh, medially rotates leg; flex knee

semimembranosus

extend thigh, medially rotates leg; flex knee

fibularis longus

palntar flex & evert foot

triceps surae

plantar flex foot

flexor digitorum longus

flexes toes, plantar flexes & inverts foot