Anatomy Lab Muscles Quiz

Muscle tone

a state of partial contraction

Length-tension relationship

the starting length of a muscle directly impacts its ability to generate tension

temporal summation

the frequency with which the muscle fibers as stimulated

motor unit recruitment

the strength of contraction is changed by varying the number of activated motor units

Isometric contraction

when a muscle develops tension but does not shorten

Isotonic contraction

when a muscle changes length during contraction

Concentric contraction

tension generated by the muscle is greater than the load and the muscle shortens

Eccentric contraction

tension generation is less than the load and the muscle lengthens

Fatigue

the progressive weakness and loss of contractibility of a muscle despite continued stimulation

Abduct

move away from midline

Adduct

Move toward midline

Medially rotate

rotate toward midline (internal rotation)

Laterally rotate

rotate away from the midline (external rotation)

Flex

Decrease angle at a joint

Extend

Increase angle at a joint

Dorsiflexion

Decrease angle between dorsum of foot and leg (elevate toes)

origin

point of attachment at stationary end

insertion

point of attachment at mobile end

belly

thick, middle part of muscle

prime mover

the muscle that produces the most force during an action

synergist

muscles that aid prime mover

antagonist

muscles that oppose the action of the prime mover

Frontalis action

elevate eyebrows

orbicularis oculi action

close eyelid

orbicularis oris action

close and protrude lips

buccinator action

compress cheek

temporalis action

elevate mandible

masseter orgin

zygomatic arch

masseter insertion

angle of mandible

masseter action

elevate mandible

sternocleidomastoid origin

sternum and clavicle

sternocleidomastoid insertion

mastoid process

sternocleidomastoid action

Together: flex neck

Alone: Rotate head

External intercostals action

elevate ribs

internal intercostals action

depress ribs

diaphragm action*

prime mover of inspiration; compress abdominal viscera

external obliques action

rotate trunk; compress abdominal viscera

internal obliques action

rotate trunk; compress abdominal viscera

rectus abdominis action

rotate trunk; compress abdominal viscera

Transverse abdominal action*

compress abdominal viscera

trapezius action

elevate and retract scapula (prime mover)

levator scapulae origin

cervical vertebrae

levator scapulae insertion

superior scapula

levator scapulae action

elevate scapula

rhomboid minor action

retract scapula

rhomboid major origin

thoracic vertebrae

rhomboid major insertion

medial scapula

rhomboid major action

retract scapula

pectoralis minor origin

ribs 3-5

pectoralis minor insertion

coracoid process of scapula

pectoralis minor action

protract scapula

serratus anterior action

protract scapula (prime mover)

erector spinae

extend trunk

elevation

levator scapulae & trapezius (superior part)

Retraction

rhomboid major, rhomboid minor & trapezius

Protraction

pectoralis minor & serratus anterior

pectoralis major action

Adduct and flex arm

latissimus dorsi action

adduct and extend arm

deltoid origin

clavicle & acromion and spine of scapula

deltoid insertion

deltoid tuberosity

deltoid action

Abduct arm (prime mover)

Teres major action

extend arm

coracobrachialis action

flex arm

Rotator cuff

Supraspinatus, Infraspinatus, Teres minor, Subscapularis (SITS)

supraspinatus origin

supraspinous fossa

supraspinatus insertion

greater tubercle

supraspinatus action

Abduct arm

Infraspinatus origin

infraspinous fossa

infraspinous origin

greater tubercle

infraspinous action

laterally rotate arm

teres minor origin

lateral scapula

teres minor insertion

greater tubercle

teres minor action

laterally rotate arm

subscapularis origin

subscapular fossa

subscapularis insertion

lesser tubercle

subscapularis action

medially rotate arm

biceps brachii action

flex elbow

brachialis

flex elbow (prime mover)

brachioradialis action

flex elbow

triceps brachialis origin

posterior humerus

triceps brachialis insertion

olecranon

triceps brachialis action

extend elbow (prime mover)

flexor carpi radialis action

flex wrist; radial flexion

flexor carpi ulnaris action

flex wrist; ulnar flexion

extensor carpi radialis longus action

extend wrist; radial flexion

extensor digitorum action

extend digits

extensor carpi ulnaris action

extend wrist; ulnar flexion

gluteus maximus action

Abduct and extend thigh

Gluteus medius action

abduct thigh

Iliopsoas action

flex thigh (prime mover)

adductor longus action

adduct thigh

adductor magnus action

adduct thigh (prime mover)

gracilis action

flex knee

sartorius action

flex thigh; flex knee

rectus femoris origin

anterior ilium

rectus femoris insertion

tibial tuberosity

Quadriceps

prime mover of knee extension

Quadriceps

rectus femoris, vastus lateralis, vastus medialis, vastus intermedius

rectus femoris action

extend knee; flex thigh

vastus lateralis origin

greater trochanter