Muscles- anatomy Flashcards
buccinator
compresses the cheek against the teeth and gums, retracts the cheek from the teeth when the mouth is closing; expel air and liquid
obitularis oculi
blinking, squinting, sleep
frontalis
raise eyebrows
obitularis oris
closes mouth, protrudes lips, speech
scalene (3)
(anterior, middle, and posterior), contracted unilaterally = cause ipsilateral flexion (tilts head toward same shoulder) contralateral rotation (rotates face away); when contracted bilaterally, they flex
the neck
sternocleidomastoid
unilateral action- tilts the head upward and toward the opposite side; its bilateral action draws the head forward and down
trapezius
extends and laterally flexes the neck
lateral pterygoid
depresses the mandible and also causes protraction and excursion
medial pterygoid
causes elevation, protraction, and excursion of the mandible
occipitalis
retracts the scalp
temporalis
elevates, retracts, and produces lateral and medial excursion of the mandible
masseter
elevates the mandible, with smaller roles in protraction, retraction, and excursion
occipitofrontalis
levator scapulae
elevates the scapula if the cervical vertebrae are fixed, flexes the neck laterally if the scapula is fixed, retracts the scapula and braces
the shoulder, and rotates the scapula and depresses the apex of the shoulder
deltoid
anterior fibers flex and medially rotate the arm; the lateral fibers abduct the arm; and the posterior fibers extend and laterally rotate the arm
diaphragm
prime mover of inspiration, responsible for two-thirds of air intake
rectus abdominus
flexes the waist, as in forward bending
external obliques
supports the abdominal viscera against the pull of gravity, stabilizes the vertebral column, maintains posture, compresses abdominal organs. Unilateral contraction causes contralateral rotation of the spine
internal obliques
has the same action as the external oblique except that unilateral contraction causes ipsilateral rotation of the waist
transverse abdominus
compresses abdominal contents, but does not contribute to movements of the vertebral column
erector spinae
latissmus dorsi
adducts and medially rotates the humerus, extends the shoulder joint, produces a backward swing of the arm, pulls the body forward and upward as in climbing, deep inspiration and sudden expiration, and supports prolonged forceful expiration as in singing
rhomboid major
retracts the scapula and braces the shoulder and fixes the scapula during arm movements
rhomboid minor
retracts the scapula and braces the shoulder and fixes the scapula during arm movements
pectoralis major
the thick, fleshy muscle of the mammary region, flexes, adducts, and medially rotates the humerus and aids in deep inspiration
pectoralis minor
draws the scapula laterally and forward around the chest wall. It also, with other muscles, rotates the scapula and depresses the apex of the shoulder
serratus anterior
draws the scapula laterally and forward around the chest wall,
protracts the scapula,
prime mover in forward-reaching and pushing actions,
aids in rotating the scapula to elevate the apex of the shoulder,
fixes the scapula during abduction of the arm
sartorius
aids in knee and hip flexion,
abducts and laterally rotates the thigh
internal intercostals
supraspinatus
aids the deltoid in abduction of the arm
resists downward slippage of the humeral head when the arm is relaxed or when carrying weight
infraspinatus
modulates the action of the deltoid, preventing the humeral head from sliding upward
rotates the humerus laterally
teres minor
modulates the action of the deltoid, preventing the humeral head from sliding upward during abduction
rotates the humerus laterally
subscapularis
modulates the action of the deltoid, preventing the humeral head from sliding upward during abduction
rotates the humerus medially
coracobrachialis
flexes and medially rotates the arm
resists deviation of the arm from the frontal plane during abduction
biceps brachii
rapid or forceful supination of the forearm, acts synergistically in elbow flexion,
flexes the shoulder slightly,
stabilizes the humeral head
brachialis
prime mover of elbow flexion
triceps brachii
prime mover of elbow extension
adducts the humerus
pronator quadratus
prime mover of forearm pronation
resists separation of the radius and ulna when force is applied
pronator teres
-assists pronator quadratus in pronation (only in rapid or forceful action)
-weakly flexes elbow
supinator
supinate forearm
flexor carpi radialis
-flex wrist anteriorly
-aids in radial flexion of wrist
*radial artery pulse landmark
flexor carpi ulnaris
-flex wrist anteriorly
-aids in ulnar flexion of wrist
flexor digitorum superficialis
-flex wrist, metacarpophalangeal, interphalangeal joints
flexor digitorum profundus
-flex wrist, metacarpophalangeal, interphalangeal joints
-sole flexor of distal interphalangeal joints
palmaris longus
anchors the skin and fascia of the palmar region and resists shearing forces
extensor carpi radialis longus
-extends the wrist
-aids in radial flexion
extensor carpi radialis brevis
-extend wrist
-aids in radial flexion
extensor digitorum
-extends the wrist, metacarpophalangeal, and interphalangeal joints
-spread digits apart when extending metacarpophalangeal joints
iliacus
-flexes the thigh at the hip when the trunk is fixed
-flexes the trunk at the hip when the thigh is fixed
-balances the trunk during sitting
(iliac+psoas major=iliopsoas)
psoas major
(iliac+psoas major=iliopsoas)
-flexes the thigh at the hip when the trunk is fixed
-flexes the trunk at the hip when the thigh is fixed
-balances the trunk during sitting
tensor fasciae latae
fibrous sheath that encircles the thigh and binds its muscles
gluteus maximus
-extends the thigh at the hip
-abducts thigh
-elevate trunk after stooping
-holds trunk erect
-stabilizes femur on tibia
gluteus medius
abduct and medially rotate the thigh
gluteus minimus
abduct and medially rotate the thigh
piriformis
laterally rotates the extended thigh and abducts the flexed thigh
adductor magnus
laterally rotates the extended thigh and abducts the flexed thigh
sartorius
aids in knee and hip flexion, as in sitting or climbing. It abducts and laterally rotates the thigh
rectus femoris
extends the knee, flexes the thigh at the hip, and flexes the trunk on the hip if the thigh is fixed
vastus lateralis
extends the knee and retains the patella in the groove on the femur during knee movements
vastus medialis
extends the knee and retains the patella in the groove on the femur during knee movements
vastus intermedius
extend the knee
biceps femoris
flexes the knee, extends the hip, elevates the trunk from a stooping posture, laterally rotates the tibia on the femur when the knee is flexed, laterally rotates the femur when the hip is extended, and counteracts forward bending at the hips
semitendinosus
flexes the knee, medially rotates tibia on the femur when the knee is flexed, medially rotates the femur when the hip is extended, and counteracts forward bending at the hips
semimembranosus
flexes the knee, medially rotates tibia on the femur when the knee is flexed, medially rotates the femur when the hip is extended, and counteracts forward bending at the hips
tibialis anterior
dorsiflexes and inverts the foot, resists backward tipping of the body, and helps support the medial longitudinal arch of the foot.
gastrocnemius
plantar flexes the foot, flexes the knee, and is active in walking, running, and jumping
(gastrocnemius +soleus=triceps surae)
soleus
plantar flexes the foot and steadies the leg on the ankle during standing
(gastrocnemius +soleus=triceps surae)
fibularis (peroneus) brevis
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) longus
maintains concavity of the sole during toe-off and tiptoeing, and everts and plantar flexes the foot
