Muscles Flashcards
What are some different shapes that the fascicles can be organized into?
circular, parallel, convergent, and pennate
What do the arrangement of fascicles influence?
ROM and power of a muscle
Most movements are coordinated by several skeletal muscles, do they work in groups or individually?
Groups
Most skeletal muscles are arranged in opposing pairs at joint, the opposing force is called the
antagonistic
A muscle that causes a desired action is referred to as the
primer mover (agonist)
The one that produces the opposite action is called the
antagonist
What is the name for the muscle that steadies a movement that prevents unwanted movements and helps the prime mover function more efficiently
synergists
Some synergists muscles in a group also act as ________, which stabilize the origin of the prime power so it can act more efficiently
fixators
_____ of muscles provide information about the muscle; like location, shape, relative size of the muscle, direction of the fascicles and muscle fibers, location of attachments, number of origins, and actions
Name
How many muscles are in the human body?
600+
What kind of connective tissue divides the limb muscles into compartments
dense fibrous CT
What are the pairs of two muscles of opposing action called
agonist/antagonist pairs
A single named ______ usually innervates each compartment
nerve
what are the 2 compartments of the upper limb
anterior and posterior
what are the 3 compartments of the thigh
anterior, posterior, and medial
What are the 3 compartments of the leg
anterior, posterior, and lateral
______ anatomy is the study of external landmarks of the body and of the internal
structures that may be observed or palpated through the body surface.
surface
How can muscles of the head and neck be grouped?
muscles of facial expression, muscles of chewing and swallowing, and muscles that move the head as a whole
_______ muscles are responsible for facial expressions
facial
what layer do facial muscles lie in?
subcutaneous layer
Face bones originate in the fascia or skull bones and insert where?
on the skin
Because of facial muscle insertions, they move the skin rather than the ______
joint
The levator palpebrae superioris that raises the upper eyelid is innervated by the oculomotor nerve which is what
CN III
- The two muscles of the scalp are connected to each other by the epicranial aponeurosis (galea aponeurotica); they are often called the ____________ or occipitofrontalis muscle:
epicranius
Which muscle raises the eyebrows
frontalis
What does the occipitalis do?
retracts the scalp
What does the orbicularis do (circles the eye)
closes the eye in blinking, squinting, and sleep
What does the levator palpebrae superioris do?
elevates the upper eyelid to open the eye
What does the corrugator supercilli do and what is it a common site for?
draws eyebrows together “frown” , common site for botox
what does the orbicularis oris do?
closes the mouth, puckers the lips (kissing)
what is the difference between the zygomatic major and minor muscle?
zygomatic minor = snarl
zygomatic major = smile (pull mouth upward -> laughing)
The buccinator forms the muscular portion of the _______, this compresses against the teeth (hold food)
cheek
What are some of the functions of the buccinator
whistling, blowing, sucking, and chewing
The ______ is a large sheet of muscle in the cervical and mental region
platysma
what facial expression does the platysma make?
horror or suprise (draws lip lower and opens mouth wide)
The extrinsic eye muscles are the 6 muscles attached to the walls of the orbit and to the external surface of the eyeball; they _____ the eye
move
6 eye muscles: ____ rectus muscles and ____ oblique muscles
4 rectus muscles and 2 oblique muscles
what are the 3 muscles that move the eye laterally?
lateral rectus, inferior oblique, superior oblique
lateral rectus
moves eye laterally
medial rectus
moves eye medially
superior rectus
elevates eye and turns it medially
inferior rectus
depresses eye and turns it medially
inferior oblique
elevates eye and turns it laterally
superior oblique
depresses eye and turns it laterally
T or F: Muscles of chewing and swallowing may contribute to facial expression, but are primarily concerned with the manipulation of food.
True
What are the functions of the temporalis
elevates, retracts, L and M mandible movement
What does the masseter do?
elevates the mandible w/ smaller roles in protraction, retraction, and excursion
is the masseter or the temporalis the primary mover of jaw closure
masseter
What is the main difference between the lateral and medial pterygoid?
lateral pterygoid = depresses and protracts mandible
medial pterygoid = elevates and protracts mandible
Muscles that move the head as a whole originate on the vertebral column, thoracic cage, and pectoral girdle, and insert on the cranial bones; a particular muscle may cause a _________ movement of the head (toward the side opposite that of the muscle) or an __________ movement (toward the same side as that of the muscle)
contralateral, ipsilateral
The flexors of the neck include 4 muscles, which is the prime mover
sternocleidomastoid (SCM)
sternocleidomastoid, when used unilaterally, turns the head from side to side contralaterally; when used bilaterally, it draws the head forward and ______.
down
The extensors of the neck are located mainly in the ______ region and tend to hold the head erect or draw it back
nuchal
What muscle holds up the head and neck
trapezius
What does the trapezius do to the scapula
stabilizes, raises, retracts, and rotates scapula
The splenius capitis produces ipsilateral flexion when acting unilaterally and ______ the head when acting bilaterally.
extend
The splenius capitis has an antogonistic relationship with which muscle
SCM
the main role of the splenius capitis is
extension
what are the 3 main categorizes for muscles of the trunk
respiration, support abdominal and pelvic floor, and mvmt of vertebral column
the muscles involved in _______ include those that enclose the thoracic cavity: the diaphragm; external intercostal muscles; and internal intercostal muscles
respiration
The diaphragm is the prime mover of _________ (responsible for 2/3 of air intake) DOME
inspiration
What is the main difference between the external intercostals and internal intercostals
external intercostals = pull ribs together to ELEVATE ribcage
internal intercostals = draw ribs together DEPRESS ribcage
What are the 3 muscle layers that enclose the lateral abdominal region
2 oblique and 1 transverse
The tendons of the oblique and transverse muscles are __________ —broad fibrous sheets.
aponeuroses
At the rectus abdominis, these sheets diverge and pass around its anterior and posterior sides, enclosing the muscle in the rectus _______
sheath
These sheets meet again at a median line called the ______ ______, between the paired rectus muscles.
linea alba
Another line, the linea _________, marks the lateral boundary where the rectus sheath meets the aponeurosis
semilunaris
The aponeurosis of the external oblique also forms a cordlike _________ ligament at its inferior margin.
inguinal
What is the function of the external abdominal oblique
supports abdominal viscera against gravity, stabilizes the vertebral column, maintain posture, compresses abdominal organs
external abdominal oblique: Unilateral contraction causes _________ rotation of the waist.
contralateral
The internal abdominal oblique has the same action except that unilateral contraction causes ________ rotation
ispilateral
The transverse abdominal compresses abdominal contents but does it contribute to movement?
No
The pair of rectus abdominis muscles are divided into segments by three transverse tendinous segments that give the abdomen a “_____ _____” appearance in physically fit individuals.
“six pack”
The rectus abdominis FLEXES the lumbar region of the vertebral column, producing
forward bending at the waist
muscles of the back primarily _______, rotate, and laterally flex the vertebral column.
extend
What are the 2 most prominent superficial back muscles that are concerned with upper limb movement
latissimus dorsi and trapezius
Which deep muscle, as it ascends divides the upper lumbar region into 3 parallel columns (run longitudinal)
erector spinae
What does the erector spinae do
EXTENSION and lateral flexion
what are the layers from lateral to medial
iliocostalis, longissimus, and spinalis = erector spinae
Muscles of the pelvic floor include ____ layers that span the pelvic outlet and support the viscera.
3 layers
what muscle is usually tweaked in older adults
quadratus lumborum (flexes)
The floor of the pelvic cavity is penetrated by the anal canal, urethra, and vagina, which open into a diamond-shaped region between the thighs called the _________
perineum
T or F: 2. The perineum is bordered by four bony landmarks: the pubic symphysis (anterior), the coccyx (posterior), and the two ischial tuberosities (lateral)
True
- The anterior half of the perineum is the _________ triangle, and the posterior half is the _______ triangle.
urogenital triangle
anal triangle
what are the 2 muscles in the superficial perineal space
ischiocavernosus and bulbospongiosus
Function of the ischiocavernosus
Retards venous drainage and maintains erection of penis or clitoris
What is the function of the bulbospongiosus
empties male urethra, assistor in erection of penis/clitoris
who is the main man in an errection?
ischiocavernosus
- The deepest compartment, the pelvic diaphragm, consists of two muscle pairs…
the levator ani and the coccygeus
what 3 muscles make up the levator ani?
iliococcygeus, pubococcygeus, and puborectalis
what is the main function of the levator ani
supports and maintains position of pelvic viscera, prevents flow when coughing but lifts anal canal to poop
in what circumstances does the levator ani stretch?
pregnancy/obesity
The _________ aids the levator ani, pulls coccyx forward when pushed back by defecation/childbirth
coccygeus
The limb muscles are organized into spaces called muscle compartments separated by _______ that contain one or more functionally related muscles along with nerve and blood supplies.
fasciae
T or F: The upper limb has anterior and posterior compartments, while the lower limb has anterior, posterior, medial, and lateral compartments.
True
These compartments are separated by the interosseous membranes of the forearm and leg and by thick fasciae called ________ ______
intermuscular septa
Thinner fascia subdivide the muscle groups into ________ and deep layers.
superficial
T or F: Muscles acting on the pectoral girdle originate on the axial skeleton and insert on the clavicle and scapula.
True
what are the 2 major muscles of the anterior group
pectoralis minor and serratus anterior
What does the pectoralis minor do?
pulls scap laterally and forward
The serratus anterior, with the pectoralis minor, draws the scapula _______ and ________ around the chest wall
laterally and forward
what is the serratus anterior the prime mover for?
PUNCHING: forward reaching and pushing acrions “the boxers muscle”
The major muscles of the _______ group are the trapezius, levator scapulae, rhomboideus minor, and rhomboideus mjor (the rhomboids)
posterior
Functions of the trapezius
stabilizes, raises, retracts, and rotates the scapula
Function of the levator scapulae
elevates and retracts scap, flexes neck
what movement is the levator scapulae known for
shrugging the shoulders
What do the rhomboids do?
Retract and stabilize the scapula
what movements are the rhomboids best known for
squaring the shoulders
Muscles acting on the arm consist of nine muscles that cross the shoulder joint and insert on the ___________
humerus
What 2 arm muscles are considered axial muscles and the prime movers of the shoulder joint
pectoralis major and latissimus dorsi
what are the functions of the pectoralis major
flexes, adducts, and medially rotates
What are the functions of the latissimus dorsi
adduction and medially rotate, extends shoulder joint
what activity is a great example of the function of the latissimus dorsi?
climbing - backward swing of arm, pulls body forward and upward in climbing
what muscle supports prolonged, forceful expiration as in singing or blowing a note on a wind instrument
latissimus dorsi
what muscle caps the shoulder and is the most conspicuous (visible) muscle
the deltoid
what about the breakdown of the direction of fibers in the deltoid such as anterior, lateral, and posterior fibers
anterior = medially rotate
lateral = abduct
posterior = laterally rotate
What does the acronym for the muscles of the rotator cuff and names?
SITS: supraspinatus, infraspinatus, teres minor, and subscapularis
The first three muscles lie on the posterior side of the scapula; the fourth, the _________ occupies the subscapular fossa on the anterior surface of the scapula.
subscapularis
Which SITS muscle lies above the scapular spine
supraspinatus
What are the functions of the supraspinatus?
aids deltoid in abduction
What does the supraspinatus do when you are carrying weight or relaxed?
resists downward slippage of the humeral head
Which muscle is inferior to the supraspinatus and the largest of the rotator cuff on the posterior side?
infraspinatus
what does the infraspinatus do?
modulate the action of the deltoid, prevent humeral head from sliding upward, and rotates humerus laterally
what are the functions of the teres MINOR?
modulates action of deltoid, prevents humeral head from sliding upward during abduction and rotates the humerus laterally
what rotator cuff muscle occupies the subscapular fossa on the anterior surface of the scapula, between the scapula and ribs
subscapularis
what are the functions of the subscapularis?
modulates action of the deltoid, preventing humeral head from sliding upward during abduction, and rotates the humerus medially (bc it is anterior)
T or F: The muscles acting on the forearm have bellies found in both the arm and the forearm itself
True
What are the 4 motions that the elbow and forearm capable of?
flexion, extension, pronation, and supination
Muscles with bellies in the arm (brachium) include the two elbow flexors in the anterior compartment (_______ and __________) and the elbow extender in the posterior compartment (triceps brachii).
brachialis and biceps brachii
What is the prime mover of elbow FLEXION?
brachialis
How many heads does the bicep branchii have?
2
What is the bicep brachii responsible for?
rapid/forceful supination of the forearm
what function does the biceps brachii act in synergy with
elbow flexion
How many heads does the tricep brachii have?
3 heads
What is the prime mover of elbow EXTENSION
triceps brachii, also adducts the humerus
Most muscles with bellies in the forearm (antebrachium) act on the wrist and hand, but two are synergists in elbow _______ and three of them function in pronation and supination.
flexion
What does the brachioradialis do?
flexes the elbow
What is the prime mover of forearm PRONATION?
pronator quadratus
what else does the pronator quadratus do -> what does it resist?
resists separation of radius and ulna when force is applied
The pronator teres assist the pronator quadratus in pronation, but only in what cases
only in rapid or forceful action (and weakly flexes the elbow)
what does the supinator do (if you miss this you are stupid)
supinates the forearm
Muscles acting on the wrist and hand include extrinsic muscles in the forearm and intrinsic muscles in the ______ itself
hand
The action of the extrinsic muscles is mainly ______ of the wrist and digits
flexion
what are some other actions of the extrinsic muscles?
radial and ulnar flexion, finger abduction and addiction, and thumb opposition
T or F: Many of them act on the metacarpophalangeal joints and the interphalangeal joints; some tendons cross multiple joints
True
Most tendons of the extrinsic muscles pass under a fibrous sheath called the ______ __________ on the anterior side of the wrist or the extensor retinaculum on the posterior side;
extensor retinaculum
the _______ _______ is a tight space between the flexor retinaculum and carpal bones.
carpal tunnel
Fascia divide the forearm muscles into anterior and posterior compartments, each of which are further divided into _________ and ______ layers.
superficial and deep
The anterior compartment, superficial layer, these muscles have the function of
flexion
What does the flexor carpi radialis do?
flexes the wrist anteriorly, aids in radial flexion of the wrist
what muscle may absent in some individuals? what percentage of people have it missing?
palmaris longus, 14% dont have it
How can you tell if you have a palmaris longus?
flex wrist and see if medial tendon pops up
what is the function of the palmaris longus
tenses the skin and fascia of the palm
what is the function of the flexor carpi ulnaris
flexes wrist anteriorly, aids in ulnar flexion of the wrist
what all doe the flexor digitorum superficialis flex?
wrist, metacarpophalangeal, and interphalangeal joints
which fingers specifically does the flexor digitorum superficialis flex
flexes 2nd to 5th fingers
The posterior compartment, superficial layer, provides the action of
extension
what does the extensor carpi radialis longus do?
extends the wrist, aids in radial flexion of the wrist
what does the extensor carpi radialis brevis do?
extends the wrist, aids in radial flexion of the wrist
What does the extensor digitorum do?
extends the wrist, metacarpophalangeal, and interphalageal joints, spread digits apart.
what is the function of the extensor carpi ulnaris
extends and fixes the wrist, aids in ulnar flexion
why may the extensor carpi ulnaris be beneficial in fighting?
fixes the wrist when the first is clenched or hand grips
The largest muscles are found in the _____ limb.
lower
T or F: They can be grouped into those that act on the femur and hip joint, those that act on the leg and knee joint, extrinsic (leg) muscles that act on the foot and ankle joint, and intrinsic (foot) muscles that act on the arches and toes
True
The anterior muscles of the hip are the _______ and the ______ _______, collectively termed the iliopsoas. They share a common tendon to the femur.
iliacus and psoas major
what does the iliacus do, when trunk and. thigh are fixed
trunk fixed: flexes thigh
thigh fixed: flexes trunk (balances trunk during sitting)
does the psoas major have the same actions as the iliacus?
yes
what is included in the lateral and posterior muscles
tensor fasciae latae (TFL) and 3 gluteal muscles
What does the tensor fasciae latae do?
extend the knee, L and M rotates the tibia, aids in abduction
the tensor fasciae latae steadies the pelvis and femur during ________
standing
what activities use the gluteus maximus which extends the thigh
stair climbing or running/walking
the gluteus maximus also adducts the thigh, what does it do to the trunk?
elevates the trunk and holds it errect
what does the gluteus maximus do to the femur
stabilizes the femur on the tibia
what do the gluteus medius and gluteus minimus do?
Abduct and medially rotate the thigh
what do the gluteus medius and minimus do during walking?
shift the weight of the trunk toward the planted limb when other foot is lifted
how do the lateral rotators oppose the action of the gluteus medius and minimus
- lateral rotators = lateral
- medial rotators = glut med and min (OPP)
What does the piriformis do?
laterally rotates the extended thigh, abducts the flexed thigh
what muscles are included in the medial (adductor) compartment
adductor brevis, adductor longus, adductor magnus, gracilis
main function of the adductor brevis
adduct the thigh
what does the adductor longus do?
adducts and medially rotates the thigh
if the adductor longus and adductor magnus both adduct and medially rotate, what makes them different
A longus = flexes thigh at hip
A Magnus = extends thigh at hip
iii. All of the adductors except the adductor _______ originate both anterior and inferior to the hip, so they are flexors, adductors and medial rotators of the thigh at the hip.
magnus
which adductor is the largest
adductor magnus
When an athlete pulls a groin muscle, he or she has torn one of the ________ muscle
adductor
what does the gracilis muscle do?
(intermost) flexes and medially rotates
The anterior (extensor) compartment of the thigh contains the quadriceps femoris, which is the prime mover of knee __________ and the most powerful muscle in the body.
extension
this compartment also includes the longest muscle in the body, what is it?
sartorius (tailors muscle)
Which muscle extends the knee, flexes the thigh at the hip, and flexes the trunk on the hip if the thigh is fixed
rectus femoris
which muscle extends the knee and retains the patella in the groove on the femur during knee movements
vastus lateralis
which muscle also has the same action as the vastus lateralis?
vastus medialis
what is the primary function of the vastus intermedius
extends the knee
The sartorius aids in knee/hip flexion; it abducts and laterally rotates the thigh -> what activities is this helpful for?
sitting or climbing
The posterior (flexor) compartment of the thigh contains three muscles colloquially known as the ____________ muscles.
hamstring (biceps femoris, semitendinosus, semimembranosus)
What does the bicep femoris do?
flexion at knee, extension & LR at hip
what action does the biceps femoris counteract?
bending at the hips
what are the functions of the semitendinosus and semimembranosus (they are the same)
flexion at knee, extension and medial rotation at hip
The posterior compartment of the leg contains one muscle that acts on the knee, the ____________; the others act on the ankle and foot.
popliteus
what does the popliteus do when sitting down (femur fixed) vs standing up (tibia fixed)
sitting down (femur fixed) = rotates tib medially
standing up (tibia fixed) = rotates tib laterally
the popliteus _____ the knee to allow flexion, prevents dislocation during crouching
unlocks
what is the big name for muscles acting on the foot
crural muscles
The fasciae separate the crural muscles into _______, _________, and __________ compartments;
anterior, posterior, and lateral
which muscle extends the toes, dorsiflexes the foot, and tightens the plantar aponeurosis
extensor digitorum longus
which muscle extends the big toe and dorisflexes the foot?
extensor hallicus longus
which muscle DF and inverts the foot, resists backward tipping of the body, and helps support the medial longitudinal arch of the foot
tibialis anterior
the flexor of the foor are located in the _______ region
sural
The first two, the gastrocnemius and the soleus, are collectively known as the _______ _______ and insert on the calcaneus via the calcaneal (Achilles) tendon.
tricep surae
which muscle PF the foot, flexes the knee, and is active in walking, running, jumping (most superficial)
gastrocnemius
which muscle also plantar flexes the foot and steadies the leg on the ankle during standing (deeper)
soleus
The flexor hallucis longus has the same actions as the flexor digitorum longus, but for the ______ toe
big
which muscle inverts the foot and may assist in strong plantar flexion or control pronation of the foot during walking
tibialis posterior
what two muscles are in the lateral compartment
fibularis (peroneus) brevis and fibularis (peroneus) longus
which muscle maintains the concavity of the sole during toe-off and tiptoeing, and may evert the foot and limit inversion and help to steady the leg on the foot
fibularis (peroneus) brevis
which muscle maintains concavity of the sole during toe-off and tiptoeing, and everts and plantar flexes the foot
fibularis (peroneus) longus
The many intrinsic muscles of the foot help to support the _______ and act on the toes.
arches
