Actions of Head/Neck/Trunk/Shoulder

56 terms by amynicole599 

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epicranius frontalis

Raises eyebrows

buccinators

Draws corner of mouth laterally; compresses cheeks, holds food between teeth

mentalis

Protrudes lower lips; wrinkles chin

epicranius occipitalis

Fixes aponeurosis and pulls scalp posteriorly

depressor labii inferioris

Draws lower lip inferiorly

masseter

Prime mover of jaw closure, elevate mandible

orbicularis oculi

Verious parts can be activated individually; closes eyes, produces blinking, squinting, draws eyebrows inferiorly

levator anguli oris

Elevates corners of the mouth

temporalis

Closes jaw; elevates and retracts mandible

levator palpebrae superioris

Raises upper eyelid or voluntarily opens the eye

depressor anguli oris

Zygomaticus antagonist; draws corners of mouth downward and laterally

medial pterygoid

Synergist of temporalis and masseter; elevates mandible; in conjunction with lateral pterygoid, aids in grinding

corrugator supercilii

Draws eyebrows medially and inferiorly; wrinkles skin of forehead vertically

depressor labii inferioris

Draws lower lip inferiorly

lateral pterygoid

Protracts jaw; in conjunction with medial pterygoid, aids in grinding teeth

levator labii superioris

Raises and furrows upper lip; opens lips

orbicularis oris

Closes lips; purses and protrudes lips (kissing and whistling muscle)

zygomaticus major/minor

Raises lateral corners of mouth upward (smile)

risorius

Draws corner of lip laterally; tenses lip; zygomaticus syngergist

platysma

Tenses skin of neck; depresses mandible; pulls lower lip back and down

digastric

Acting in concert, elevate hyoid bone; open mouth and depress mandible

geniohyoid

Pulls hyoid bone superiorly and anteriorly shortening the floor of the mouth, it draws the tongue forward

mylohyoid

Elevates hyoid bone and base of tongue during swallowing

thyrohyoid

Depresses hyoid bone; elevates larynz if hyoid is fixed

scalenes

Flex and slightly rotate neck; elevate ribs 1-2 (aid in inspiration)

sternocleidomastoid

Contraction of both muscles of pair causes flexion of neck forward, generally against resistance, acting independently, rotate head toward shoulder on opposite side

stylohyoid

Elevates and retracts hyoid bone

sternohyoid

Acting with sternothyoid and omohyoid depressed larynx and hyoid bone if madible is fixed, may also flex skull

sternothyroid

Lateral and deep to sternohyoid, same action

omohyoid

Straplike with two bellies, lateral to sternohyoid with same actions

pectoralis major

Prime mover of arm flexions; adducts, medially rotates arm; with arm fixed, pulls chest upwards (forced inspiration)

rectus abdominis

Flexes and rotates vertebral column; increase abdominal pressure; fixes and depresses ribs; stabilizes pelvis during walking; used in sit-ups

infraspinatus

Lateral rotations of humerus; helps hold head of humerus in glenoid cavity; stablizes shoulder

rhomboideus minor

Retracts and stabilizes the scapula, elevates the vertebral border, and rotates the scapula to depress inferior angle

serratus anterior

Prime mover to protract and hold scapula against chest wall; rotates scapula, causing inferior angle to move laterally and upward; essential to raising arm; fixed scapula for arm abduction

external oblique

Most superficial lateral muscle, compresses abdominal wall; also aids muscle of back in trunk rotation and lateral flexions; used in oblique curls

teres minor

Small muscle inferior to infraspinatus (same actions); a rotator cuff muscle

semispinalis

Actin together, extend head and vertebral column; acting independently (right vs. left) causes rotation towards opposite side

deltoid

Acting as a whole, prime mover of arm adduction; when only specific fibers are active, can aid in flexion, extension, and rotation of humerus

internal oblique

Most superficial lateral muscles, same as external oblique

teres major

Extends, medially rotates, and adducts humerus; synergist of lattisimus dorsi

erector spinae

Extend and bend the vertebral column laterally; fibers of the longissimus also extend head

pectoralis minor

With ribs fixed, draws scapula forward and inferiorly; with scapula fixed, draws rib cage superiorly

transversus abdominis

Compresses abdominal contents

supraspinatus

Initiates abduction of humerus; stabilizes shoulder joints

splenius

As a group extend of hyperextend head; when only one side is active, head is rotated and bent towards same side

external intercostals

Pull ribs toward one another to elevate rib cage; aid in inspiration

trapezius

Extends head; raises, rotates, and retracts scapula and stabilizes it; superior fibers elevate scapular (shrugging shoulders); inferior fibers depress it

levator scapulae

Elevates and adducts scapula; with fixed scapula, laterally flexes neck to the same side

quadratus lumborum

Each flexes vertebral column laterally; together extend the lumbar spine and fix rib 12; maintains upright posture

internal intercostals

Draw ribs together to depress rib cage; aid in forced expiration

latissimus dorsi

Prime mover of arm extensions; adducts and medially rotates arm; brings arm down in power stroke, as in striking a blow

rhomboideus major

Adducts, retracts, elevates, and rotates the scapula so that the glenoid cavity faces downward and stablizes the scapula

diaphragm

Prime mover of inspiration flattens on contractions

subclavius

Depresses clavicle and draws shoulder forward and downward

subscapularis

Medially rotates and stablizes the head of the humerus in the glenoid cavity

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