Chapter 10 Flashcards
Epicranius
Bipartite muscle consisting of the frontalis and occipitalis muscles connected by a cranial aponeurosis the galea aponeurotica; pulls the scalp forward and backward
Frontalis
Covers forehead and dome of skull. raises the eyebrows and wrinkles forehead skin horizontally
Occipitalis
fixes aponeurosis and pulls scalp posteriorly
Corrugator supercilii
draws eyebrows together and inferiorly; wrinkles skin of forehead vertically (as in frowning)
Orbicularis oculi
protects eyes from intense light and injury; various parts can be activated individually; produces blinking squinting, and draws eyebrows inferiorly
zygomaticus
raises lateral corners of mouth upward (smiling muscle)
Risorius
Draws corner of lip laterally ;tenses lips; synergist of zygomaticus
Levator labii superioris
opens lips; raises and furrows the upper lip
Depressor labii inferioris
draws lower lip inferiorly (as in a pout)
Depressor anguli oris
zygomaticus antagonist; draws corners of mouth downward and laterally (as in a “tragedy mask” grimace)
Orbicularis oris
closes lips; purses and protrudes lips; kissing and whistling muscle
Mentalis
protrudes lower lip; wrinkles chin
Buccinator
draws corner of mouth laterally; compresses cheek (as in whistling and sucking); holds food between teeth during chewing; well developed in nursing infants
Platysma
Helps depress mandible; pulls lower lip back and down, i.e., produces downward sag of mouth; tenses skin of neck (e.g., during shaving)
Masseter
Prime mover of jaw closure; elevates mandible
Temporalis
closes jaw; elevates and retracts mandible; synergist of pterygoids (see below) in side-to-side movements; maintains position of the mandible at rest
Medial Pterygoid
Synergist of temporalis and massester muscles in elevation of the mandible; acts with the lateral pterygoid muscle to protrude mandible and to promote side-to-side grinding movements
Lateral Pterygoid
Protrudes mandible (pulls it anteriorly); provides forward sliding and side-to-side movements of the lower teeth
Genioglossus
Primarily protrudes tongue, but can depress or act in concert with other extrinsic muscles to retract tongue
Hyoglossus
Depresses tongue and draws its sides downward
Styloglossus
Retracts (and elevates) tongue
Digastric
Acting in concert, the digastric muscles elevate hyoid bone and steady it during swallowing and speech; acting from behind they open mouth and depress mandible
Stylohyoid
elevates and retracts hyoid, thereby elongating floor of mouth during swallowing
Mylohyoid
Elevates hyoid bone and floor of mouth, enabling tongue to exert backward and upward pressure that forces food bolus into pharynx
Geniohyoid
Pulls hyoid bone superiorly and anteriorly, shortening floor of mouth and widening pharynx for recieving food
Sternohyoid
Depresses larynx and hyoid bone if mandible is fixed; may also flex skull
Sternothryoid
Pulls thyroid cartilage (pulls larynx and hyoid bone) inferiorly
Omohyoid
Depresses and retracts hyoid bone
Thryohyoid
Depresses hyoid bone and elevates larynx if hyoid is fixed
Pharyngeal constrictor muscles
Working as a group and in sequence, all constrict pharynx during swallowing, which propels a food bolus to esophagus
Sternocleidomastoid
Prime mover of active head flexion
Scalenes
Elevate first two ribs (aid in inspirationg) flex and rotate neck
Splenius
Act as a group to extend or hyperextend head, when spelnuis muscles on one side are activated, head is rotated and bent laterally toward same side
Iliocostalis
Extend vertebral column, maintain erect posture, acting on one side, bend vertebral column to same side
Longissiumus
Throacis and cervicis act together to extend vertebral column and acing on one side, bend it laterally; capitis extends head and turns the face toward same side
Spinalis
Extends vertebral column
Semispinalis
Extends vertebral column and head and rotates them to opposite side; acts synergistically with sternocleidomastoid muscles of opposite side
Quadratus Lumborum
Flexes vertebral column laterally when acting spearately; when pair acts jointly, lumbar spine is extended and 12th rib is fixed; maintains upright posture asists in forced inspiration
4 muscles in vertebraes
Intertanscersarius, rotatores, multifidus, interspinales
External intercostals
with first ribs fixed by scalene muscles, pull ribs toward one another to elevate rib cage; aids in inspiration; synergists of diaphragm
Internal intercostals
with 12th ribs fixed by quadratus lumborum, muscles of posterior abdominal wall, and oblique muscles of the abdominal wall, they draw ribs together and depress rib cage; aid in forced expiration
Diaphragm
Prime mover of inspiration; flattens on contraction, increasing vertical dimensions of thorax, when strongly contracted, dramatically increases intra-abdominal pressure
Rectus abdominis
Flex and rotate lunbar region of vertebral column; fix and depress ribs, stabalize pelvis during walking, increase intra-abdominal pressure
External Oblique
When pair contract simultaneously, aid rectus abdominis muscles in flexing vertebral column and in compressing abdominal wall
Internal oblique
as for external oblique
Transverses Abdominis
Compresses abdominal contents
