Anatomy - The Muscular System

Front 1

What are origin and insertion?

Back 1

origin - stationary attachment (usually proximal)

insertion - movable attachment (usually distal)

Front 2

What is an example of a muscle that moves a body part it doesn't cover?

Back 2

biceps brachii moves the forearm

Front 3

What are examples of muscles that cross two joints?

Back 3

rectus femoris and sartorius

Front 4

What are lever, fulcrum, effort, and load?

Back 4

Lever - moves around fixed point called fulcrum

Fulcrum - fixed point on which lever moves

Effort - force due to muscular contraction, used to move load

Load - weight that is moved or resistance offered by an object to being moved

Front 5

Examples of Levers and Fulcrums

Back 5

Levers - bones

Fulcrums - joints

Front 6

What is Mechanical advantage/disadvantage?

Back 6

Advantage - large load over small distance, more for strength

Disadvantage - load to be moved over large distance, more for speed and distance

motion occurs when effort > load

Front 7

What is the Law of Levers?

Back 7

When fulcrum-effort distance > fulcrum-load distance = mechanical advantage

fulcrum-effort distance < fulcrum-load distance = mechanical disadvantage

Front 8

What are First Class Levers and Examples?

Back 8

very few in our body

fulcrum is between effort and load (EFL)

mechanical advantage/disdvantage

ex. mandible at TMJ (advantage), humerus at shoulder joint (disadvantage), scissors, and seesaws, head resting on vertebral column (atlantocciptal joint)

Front 9

What are Second Class Levers and Examples?

Back 9

FLE (fulcrum-load-effort), uncommon

always mechanical advantage because load always closer to fulcrum than effort

ex. plantar flexion - F = foot, E = calcaneus, and L = body; push-ups - F = foot, E = hands, L = body's center of gravity; wheelbarrow, nut cutter

produce force at cost of speed

Front 10

What are Third Class Levers and Examples?

Back 10

FEL, most common in body

always mechanical disadvantage because effort is always closer to fulcrum

produce speed at cost of force

ex. elbow flexion, knee flexion

Front 11

What are the 5 patterns of fascicles?

Back 11

Parallel - run parallel to long axis
ex. SCM, stylohyoid, sartorius

Convergent/Triangular - origin broad, fascicles converge toward tendon of insertion
ex. Pectoralis major

Fusiform - parallel to longitundinal axis, terminate in flat tendons
ex. Digastric muscle, biceps brachii

Unipennate - insert into one side of tendon, ex. Digitorum longus

Bipennate - fascicles insert into both sides, ex. Rectus Femoris

Multipennate - insert into one large tendon from all sides, ex. Deltoid

Circular - arranged in concentric rings, surround external body openings
ex. Obicularis oris and oculi

Front 12

Power vs. Range of Motion in Fascicles

Back 12

Longer fibers = greater range of motion

larger cross-sectional area = greater power

Front 13

What are agonists and antagonists?

Back 13

agonist - prime mover responsible for action

antagonist - stretches against agonist

ex. forearm flexion - biceps = agonist, trips = antagonist

if agonist and antagonist contract at same time = no movement

Front 14

What are synergists and what do they do?

Back 14

contract and stabilize the intermediate joints

aid movement of agonist and prevent unwanted movements at other joints

ex. wrist extensor muscles stabilize wrist joint while flexor muscles of fingers contract as prime mover

Front 15

What are fixators?

Back 15

stabilize origin of agonist so it acts more efficiently

ex. muscles in scapula can be agonists (deltoid) or fixators (pectoralis minor, trapezius, subclavius)

Front 16

What is Tenosynovitis?

Back 16

inflammation of tendons, tendon sheaths, and synovial membranes surrounding certain joints

most often affected tendons:

wrist
shoulders
elbows (tennis elbow)
finger joints (trigger finger)
ankles and feet

caused by trauma, strain, or excessive exercise (gymnasts, typists, hairdressers, carpenters)

Front 17

What are intramuscular injections?

Back 17

used for prompt absorption of drugs or too irritating on skin

common IM sites:

gluteus medius
vastus lateralis
deltoid

faster than oral but slower than IV

Front 18

What are the 7 features used to name skeletal muscles?

Back 18

1. pattern of fascicles (rectus and transverse abdominis)
2. size (maximus, minimus)
3. shape (deltoid - triangular)
4. action (flexor, extensor)
5. number of origins (biceps, triceps)
6. location (brachialis)
7. sites of origin and insertion (brachioradialis)

Front 19

What are examples of sphincters and dilators?

Back 19

sphincter - obicularis oculi (closes the eye)

dilator - levator palpebrae superioris (opens the eye)

Front 20

What are the muscles of facial expression?

Back 20

Occipitofrontalis - raises eyebrows (wrinkles forehead in surprise look)

Orbicularis oculi - encircles the eyes, allows blinking (aids passage and drainage of tears)

Orbicularis oris - encircles the mouth, moves the lips (protrudes and closes lips as in kissing)

Buccinator - pucker the mouth (doesn't attach to bone)

Zygomaticus - smiling muscle (cheek)

Levator labii superioris - sneering (elevates and everts upper lip)

Depressor anguli oris - frowning and pouting

Front 21

What are some other functions of the Occipitofrontalis and Buccinator?

Back 21

Occipitofrontalis - wrinkles forehead like a look of surprise
has frontal belly and occipital belly
both are held together by an aponeurosis named epicranial aponeurosis or gale aponeurotica

Buccinator - muscle forms the major muscular portion of the cheek
-compresses the cheeks during blowing actions like playing trumpet
-also responsible for actions like whistling, sucking and assists in chewing

Front 22

What are the actions of the Zygomaticus Major/Minor and Risorius?

Back 22

Zygomaticus Major - elevates and draws angle of mouth laterally and superiorly as in smiling

Zygomaticus Minor - elevates and everts upper lip, exposes maxillary teeth

Risorius - retracts angle of mouth as in grimacing

Front 23

What are the actions of Depressor Labii Inferioris, Depressor Anguli Oris, and Platysma

Back 23

Platysma - depresses and wrinkles the skin of lower face and mouth. Aids forced depression of mandible

Depressor Anguli Oris - depresses and draws angle of mouth laterally and inferiorly as in opening of mouth

Depressor Labii Inferioris - depresses and draws lower lip laterally

Front 24

What are the actions of the Corrugator supercilii and Temporalis?

Back 24

Temporalis - elevates mandible (and posterior fibers retract)

Corrugator Supercilii - wrinkles forehead vertically as in frowning

Front 25

What are the functions of the Masseter and Mentalis?

Back 25

Mentalis - eleveates and wrinkles skin of chin and protrudes lower lip

Masseter - elevates mandible (enables forced closure of mouth), strongest muscle in mastication

Front 26

What are some causes of Bell's Palsy?

Back 26

inflammation of facial nerve due to an ear infection

ear surgery that damages the facial nerve

infection by the herpes simplex virus

Front 27

What are the muscles of mastication?

Back 27

Medial/Lateral Pterygoid - move mandible side to side

Masseter - closure of jaw (strongest)

Temporalis - closure of jaw (elevates mandible)

all innervated by Trigeminal Nerve

Front 28

What are extrinsic eye muscles and examples?

Back 28

muscles that move the eyeballs, originate outside of eyeballs and insert on outer surface of sclera

1. Superior and Inferior Recti - move eyeball superiorly and inferiorly

2. Lateral and Medial Recti - move eyeball medially and laterally

3. Superior Oblique - moves eyeball inferiorly and laterally

4. Inferior Oblique - moves eyeball superiorly and laterally

four muscles arise from the tendinous ring in the orbit and insert into the sclera of the eye

Front 29

What is the levator palpebrae superioris?

Back 29

does NOT move eyeballs

raises upper eyelids, opening the eyes

acts as antagonist to orbiularis oculi, which closes the eyes

Front 30

What are some general actions of Eye Muscles?

Back 30

Superiors - medially rotate
Inferiors - laterally rotate
Obliques - abduct
Recti - adduct
Superior oblique - depresses
Inferior Oblique - elevates

Front 31

What is Strabismus?

Back 31

condition where two eyeballs are not properly aligned (lazy eye)

external strabismus - occulomotor nerve, inability to move eyeball medially and inferiorly

internal strabismus - abducens nerve, cannot move laterally

Front 32

What are the extrinsic tongue muscles?

Back 32

Genioglossus - depresses tongue and forward (protraction)

Styloglossus - elevates tongue and retraction

Hyoglossus - depresses tongue and flattens it (draws down on both sides)

Palatoglossus - raises back portion of tongue

Front 33

What is Endotracheal intubation?

Back 33

tube is inserted from the oral cavity through the laryngopharynx into the trachea

this is done during anesthesia to prevent obstruction of airway to lungs by genioglossus muscle

Front 34

What are the Muscles of the Anterior neck that help in swallowing and speech?

Back 34

Suprahyoid - located above hyoid bone, elevate the hyoid bone, floor of the oral cavity and tongue during swallowing

infrahyoid (strap) - below hyoid, depresses hyoid bone, some move the larynx during swallowing and speech

Front 35

What are the Suprahyoid mm?

Back 35

Stylohyoid - elevates and draws hyoid bone posteriorly (aids in swallowing)

Mylohyoid - elevates hyoid bone and floor of mouth, depresses mandible (aids in mastication and swallowing)

Geniohyoid

Digastric - elevates hyoid bone and larynx (aids in swallowing and speech) and depresses mandible

Front 36

What are the Infrahyoid mm?

Back 36

Omohyoid - two bellies; depresses the hyoid bone

Sternohyoid - depresses hyoid bone and thyroid cartilage of larynx

Sternothyoid - depresses thyroid cartilage of larynx

Thryohyoid - depresses hyoid bone, elevates thyroid cartilage to roduce low and high tones during phonation

Front 37

What are the Triangles of the neck that the SCM divides?

Back 37

Anterior - contains submental, submandibular and deep cervical lymph nodes, submandibular gland and part of parotid gland, facial artery and vein, common carotid artery and internal jugular vein and CN IX, X, XI, XII

Posterior - part of subclavian artery, external jugular vein, cervical lymph nodes, brachial plexus and CN XI

Front 38

What are the actions of the SCM, Splenius Capitis, and Semispinalis Capitis?

Back 38

SCM - (bilaterally) flex cervical portion and head, elevate sternum during forceful inhalation, (unilaterally) rotate head to side opposite contracting muscle

Splenius Capitis - acting together, extend head; acting singly, rotate head to side opposite of contracting muscle

Semispinalis Capitis - same as splenius capitis

Front 39

What are the 4 muscles of the Abdomen?

Back 39

External Oblique - superficial muscle, fascicles extend inferiorly and medially, same as internal oblique

Internal Oblique - flat muscle, right angle to external oblique, (bilaterally) compresses abdomen and flexes vertebral column; (unilaterally) flexes vertebral column and rotates it

transversus abdominis - deep muscle, transversely around abdominal wall, compresses abdomen

these three form protective layer of muscles around abdomen, aponeurosis of 3 forms rectus sheaths and encloses rectus abdominis

rectus abdominis - long muscle that extends entire length of anterior abdominal wall (interrupted by tendinous intersections), compresses abdomen to aid in defecation, urination, and childbirth, flexes trunk

Front 40

What are the functions of the abdominal wall?

Back 40

protect abdominal viscera

flex and rotate IV joints

compress abdomen during exhalation

produce force needed for defecation, urination, and childbirth

Front 41

What is the linea alba?

Back 41

connective tissue band extending from xiphoid process to pubic symphysis, where the rectus sheaths meet at the midline

Front 42

What are the inguinal ligament and canal?

Back 42

ligament - inferior free border of the external obliuq aponeurosis

canal -
males: ilioinguinal nerve and spermatic cord
females: round ligament of uterus and ilioinguinal nerve

Front 43

Anterior vs. Posterior Abdominal wall

Back 43

posterior is bulky and more stable

anterolateral can contract and distend

Front 44

What is an inguinal hernia?

Back 44

rupture or separation of a portion of inguinal area of the abdominal wall resulting in protrusion of a part of the small intestine

more common in males

surgery to "tuck" back cavity, mesh repairs weak muscles

Front 45

What are the 3 orifices in Diaphragm?

Back 45

1. Aortic hiatus - aorta, thoracic duct, and azygous vein pass

2. Esophageal hiatus - esophagus and vagus nerve pass

3. Caval opening - IVC passes

Front 46

What is hiatus hernia?

Back 46

stomach protrudes through esophageal hiatus

Front 47

What are internal/external intercostal muscles?

Back 47

external - superficial layer, for inhalation

internal - intermediate layer, for FORCED exhalation

innermost - poorly developed

Front 48

What are the muscles of the pelvic diaphragm?

Back 48

Levator ani - formed from iliococcygeus and pubococcygeus, supports pelvic viscera and resists intra-abdominal pressure

ischiococcygeus - pulls coccyx anteriorly and pushed posteriorly during defecation or child birth

Front 49

What happens when Levator Ani gets injured?

Back 49

caused by difficulty in child birth

causes urinary stress incontinence

Front 50

What is the perineum?

Back 50

diamond shaped area that extends from pubic symphysis anteriorly --> coccyx posteriorly --> ischial tuberosities laterally

separated into anterior urogenital and posterior anal trangles by transverse line between ischial tuberosities

Front 51

What muscles are in the superficial and deep layers of the perineum?

Back 51

superficial - superficial transverse perineal muscle, bulbospongiosus, and ischiocavernosus

deep -
male: deep transverse perineal muscle and external urethral sphincter
female: compressor urethrae, sphincter urethrovaginalis and external urethral sphincter

Front 52

Muscles and function of Pectoral Girdle?

Back 52

function is to stabilize scapula, increase range of motion of humerus

Anterior thoracic muscles -
subclavius: pulls clavicle towards sternum
pec minor: abduct the scapula, pulls it foward and downward
serratus anterior: impt in punching and pushing, abducts scapula and rotates it upward

posterior thoracic muscles -
trapezius: elevates shoulder and laterally rotates scapula
levator scapulae: elevates scapula and rotates it downward
rhomboid major: elevates and adducts scap and rotates it downward
rhomboid minor: same as major

Front 53

What are the movements of the scapula?

Back 53

elevation - ex. shrugging shoulders or lifting a weight over head

depression - ex. pulling down a rope

abduction (protraction) - ex. push ups or punching

adduction (retraction) - ex. rowboat

upward rotation - ex. jumping jack

downward rotation - ex. gymnast balancing

Front 54

Where are muscles that attach to scapula and thorax and move scapula?

Back 54

trapezius - shoulders and upper back, extends neck and head

serratus anterior - between ribs, elevates ribs

levator scapulae, rhomboids & pectoralis minor - act as fixators to hold the scapula in position

Front 55

What are considered the scapular muscles?

Back 55

deltoid
subscapularis
spraspinatus
infraspinatus
teres major
teres minor
coracobrachialis

Front 56

What muscles originate in the axial skeleton?

Back 56

Pectoralis major - adducts and medially rotates the arm at shoulder joint, clavicular head flexes arm and sternocostal head extends flexed arm to side of trunk

Latissimus dorsi - adduction, medial rotation and extension of arm at shoulder joint, "swimmer's muscle"

Front 57

What are the muscles of the rotator cuff?

Back 57

Subscapularis - medially rotates arm at shoulder joint

Infraspinatus - rotates arm laterally and adducts arm at shoulder joint

Teres Minor -

Supraspinatus - assists deltoid to abduct the arm (1st 15 degrees) at shoulder joint

Front 58

What are the actions of the deltoid and teres major mm?

Back 58

Deltoid - abduction of arm from 15-90 degrees

Teres Major - extends the arm, adducts and rotates medially at shoulder joint

Front 59

What is Impingement Syndrome?

Back 59

inflammation of supraspinatus muscle with continuous, repetitive movement of arm over head

usually happens to sportspersons

Front 60

What is Rotator Cuff injury?

Back 60

continued movement despite pain from impingement sydnrome leading to tearing away of bone and tendon degeneration near attachment to humerus

Front 61

What are the forearm flexors?

Back 61

form anterior compartment

biceps brachii - flexes arm at elblow joint, supinates forearm at RU joint

brachialis - flexes forearm at elbow joint

brachioradialis - flexes forearm at elbow joint, supinates and pronates forearm

Front 62

What are the forearm extensors?

Back 62

form posterior compartment

triceps brachii - extends arm at shoulder joint and extends forearm at elbow joint

anconeus

Front 63

What are the muscles involved in pronation and supination?

Back 63

Pronation:
pronator quadratus - pronates foearm
pronator teres - pronates and flexes forearm

Supination:
supinator - supinates forearm

Front 64

What are the five principal movements of the thumb?

Back 64

flexion, extension, abduction, adduction, and opposition

Front 65

What muscles attach the arm to the thorax

Back 65

pectoralis major - adducts the arm and flexes the shoulder

latissimus dorsi - medially rotates and adducts arm and extends shoulder

Front 66

Parts of Anterior (Flexor) compartment of Upper Limb

Back 66

superficial -
flexor carpi radialis - flex forearm and hand, abduction of hand
palmaris longus - flexes hand and wrinkles skin of palm of hand
flexor carpi ulnaris - flexes forearm and hand, adducts hand
flexor digitorum superficialis - flexes phalanges, wrist, and forearm

digitorum superficialis is deep to other 3 and largest

deep -
flexor pollicis longus - flexes thumb
flexor digitorum profundus - flexes phalanges

flexor pollicis longus is only flexor at distal phalanx of thumb

Front 67

Parts of Posterior (Extensor) Compartments of Upper Limb

Back 67

Superficial:
Extensor Carpi Radialis Longus - extends and abducts the wrist
Extensor Carpi Radialis Brevis - tends and abducts the wrist
Extensor Digitorum - extends fingers, hand, and forearm
Extensor Digiti Minimi - extends little finger
Extensor Carpi Ulnaris - extends and adducts the hand

Deep:
Abductor Pollicis Longus - abducts thumb
Extensor Pollcis Longus - extends thumb
Extensor Pollicis brevis - extends thumb
Extensor indicis - extends index finger

Front 68

What are the 3 groups of intrinsic hand muscles?

Back 68

Thenar - thenar muscles plus adductor pollicis form the thenar eminence

Hypothenar - muscles that act on little finger make up hypothenar eminence

Intermediate

Front 69

What does the Scalene group do?

Back 69

flex and rotate the head and assist in deep inhalation

Front 70

What do the Iliopsoas, Gluteus Maximus and Minimus do?

Back 70

Iliopsoas (psoas major and iliacus) - flexes hip, anterior muscle

gluteus maximus - extends hip and abducts thigh

gluteus minimus - hip, abducts and rotates thigh

maximus, medius, and minimus all extend and abduct femur

Front 71

What is the muscle of the medial (adductor) compartment?

Back 71

Gracilis - adducts femur

Front 72

What are the muscles of the Anterior (extensor) compartment of the lower limb?

Back 72

Quadriceps Femoris -
Rectus femoris: anterior
Vastus Lateralis: lateral
Vastus Medialis: medial
Vastus Intermedius: deep to rectus

Sartorius - long, narrow muscle that forms band

Front 73

What are the muscles of the posterior (flexor) compartment that make up the hamstrings?

Back 73

biceps femoris

semitendinosus

semimembranosus

both extensors and flexors because they span two joints

Front 74

What are the muscles of the anterior compartment of the foot?

Back 74

all dorsiflex the foot

tibialis anterior
extensor hallicus longus
extensor digitorum longus
fibularis tertius

Front 75

What are the muscles of the lateral compartment of the foot?

Back 75

plantar flex and evert the foot

fibularis longus
fibularis brevis

Front 76

What are the muscles of the posterior compartment of the foot?

Back 76

superficial - insert onto calcaneal (achillis) tendon
gastrocnemius -
soleus
plantaris
known as the calf muscles

deep -
popliteus
tibialis posterior
flexor digitorum longus
flexor hallicus longus

Front 77

What is the muscle on the dorsum of the foot?

Back 77

extensor digitorum brevis

Front 78

What are the muscles on the sole of the foot (4 layers)?

Back 78

First Layer: flexor digitorum brevis, abductor hallucis, abductor digiti minimi

Second Layer: flexor accessorius, lumbricals

Third Layer: flexor hallucis brevis, adductor hallucis, flexor digiti minimi brevis

Fourth Layer: plantar and dorsal interossei

Front 79

αἷμα; αἵματος, τό

Back 79

blood