11 Muscle Flashcards
Frontal belly of occipitofrontalis
raises eyebows and wrinkles forehead
Orbicularis oculi
Sphincter muscle around eye, closes eye
Orbicularis oris
Sphincter muscle around mouth, closes lips, protrudes lips as in kissing
Zygomaticus major
Raises corners of mouth and upper lip posteriorly and superiorly (as in smiling)
Mentalis
attaches to lower lip, chin muscle, Protrudes lower lip (pout)
Buccinator
Cheek muscle, compresses cheek, holds food between teeth while eating. (babies use it for suckling)
Platysma
Thin superficial sheet of muscle on neck. Pulls lower lip inferiorly, tenses neck skin
Depressor anguli oris
Pulls corner of mouth inferiorly
Temporalis
Elevates mandible and pulls posteriorly (retracts)
broad, fan shaped
from temporal line of skull to coronoid process of mandible
Masseter
Elevates mandible and pulls anteriorly (retracts) prime mover closing jaw
most powerful and important masticatory muscle
Lateral Pterygoid
Side to side movement of mandible, protracts mandible
Medial Pterygoid
Elevates and protracts mandible, side to side movement of mandible
Sternocleidomastoid
extends from sternum and clavicle to mastoid process
If one muscle contracts it rotates head to opposite side. If both muscles contract causes head flexion.
Scalene
anterior, middle and posterior
works with sternocleidomastoid to flex neck
extends from transverse prcess of cervical vertebrae
elevates first and second ribs during forced inhalation
Trapezius
Diamond shaped muscle
Extends form the skull and vertebral column to pectoral girdle
Elevates and depresses scapula. Extends head.
Erector spinae group: spinalis
Most medial.
nserts on spinous processes of vertebrae
composed of cervical and thoracic parts
If one muscle contracts causes lateral flexion of vertebral column. If both muscles contract causes back extension.
Erector spinae group: longissimus
Intermediate of the three.
inserts on vertebrae transverse processes
composed of capitis, cervical, and thoracic parts
If one muscle contracts causes lateral flexion of vertebral column. If both muscles contract causes back extension.
Erector spinae group: iliocostalis
Most lateral.
has cervical thoracic and lumbar parts
If one muscle contracts causes lateral flexion of vertebral column. If both muscles contract causes back extension.
splenius capitis, splenius cervicis, semispinalis, longissimus capitis
posterior neck muscles
when contracted bilaterally, extend neck
when contracted unilaterally, turn head and neck to same side
diaphragm
dome-shaped muscle
partitions thoracic and abdominal cavities
most important muscle associated with breathing
fibers conversing toward a fibrous central tendon
contracts during inspiration
External intercostals
extends inferomedially from superior rib to adjacent inferior rib
Elevates ribs during inspiration (fibers run inferior and anterior)
Internal intercostals
deep to external intercostals, fibers at right angles to external intercostals
Depresses ribs during forced expiration (fibers run inferior and posterior)
transversus thoracis
depresses ribs during forced expiration
External oblique
superficial, fibers directed inferomedially
muscular along lateral abdominal wall, forms aponeurosis anteriorly
If one side contracts causes rotation at waist. If both muscles contract causes compression of abdomen (fibers run inferior and medial)
Internal oblique
immediately deep to external oblique
fibers projecting superomedially, forms aponeurosis projecting anteriorly
If one side contracts, causes rotation at waist.
If both muscles contract causes compression of abdomen and stabilize vertebral column (fibers run superior and medial) Deep to external oblique.
Transversus abdominis
deepest muscle
fibers projecting transversely, forms aponeurosis anteriorly
Compresses abdomen. Deep to internal oblique (fibers run horizontal)
Rectus abdominis
long muscle extending vertically
partitioned into four segments by fibrous tendinous intersections
enclosed within a fibrous sleeve, rectus sheath (connected by linea alba)
formed from aponeuroses of external and internal oblique, transversus
Flexes vertebral column
Linea alba (not a muscle)
White line of strong connective tissue at midline from xiphoid process to pubic symphysis.
Pectoralis minor
Moves scapula anteriorly and down, when contracted shoulders hunch forward
deep to pectoralis major
Serratus anterior
fans shaped muscle between ribs and scapula
superior rotator of the scapula (e.g., upper limb abduction)
Agonist in scapula protraction, stabilizes scapula.
levator scapulae
originates from transverses processes of cervical vertebrae
inserts on superior angle of scapula
elevates and inferiorly rotates the scapula
rhomboid major and minor
deep to the trapezius
runs inferolaterally from vertebrae to scapula
helps elevate, retract, and inferiorly rotate the scapula
Pectoralis major
thick fan-shaped muscle on superior thorax
prime arm flexor; adducts, medially rotates
Latissimus dorsi
broad triangular muscle on inferior back
prime arm extensor; adducts, medially rotates
Deltoid
Prime mover abduction of arm and rotation of arm
Subscapularis
Stabilize and medial rotates shoulder Rotator Cuff
used when winding up for a pitch
Supraspinatus
Stabilize and abducts shoulder
Rotator Cuff
used when starting to execute pitch
Infraspinatus
Stabilize and adducts shoulder Rotator Cuff
slows down arm on completion of pitch
with teres minor
Teres minor
Stabilize and adducts shoulder Rotator Cuff
slows down arm on completion of pitch
with infraspinatus
Brachialis
Prime mover forearm flexion
deep to biceps brachii
most powerful flexor of forearm
Biceps brachii
large two-headed muscle on anterior humerus
one of the two primary flexors of the forearm
supinator of the forearm when elbow flexed
weakly helps flex the humerus
long head originates on supraglenoid tubercle of scapula
assists in flexing the arm
Triceps brachii
long head originates on infraglenoid tubercle, spans joint
major extensor of the forearm
also helps extend the humerus
helps extend and adduct the arm
Brachioradialis
Forearm flexion
on anterolateral forearm
synergistic in elbow flexion
Flexor carpi radialis
Flexes wrist and abducts hand
Flexor carpi ulnaris
Flexes wrist and adducts hand
Flexor digitorum
Flexes phalanges
Extensor carpi radialis
Extends wrist and abducts hand
Extensor carpi ulnaris
Extends wrist and adducts hand
Extensor digitorum
Extends phalanges
Iliacus (part of Iliopsoas)
Psoas major (part of iliopsoas)
anterior thigh
originate on lumbar vertebrae and ilium
merge and insert on femur as iliopsoas
work synergistically to flex the thigh
tensor fasciae latae
lateral thigh
abducts and medially rotates the thigh
attaches to lateral thickening of fascia lata
termed iliotibial tract
adductor brevis, adductor longus, adductor magnus
medial thigh
adducts the thigh
brevis and longus also flex the thigh
magnus also extends and laterally rotates the thight
Gracilis
medial thigh
Adducts and flexes thigh
Biceps femoris
(part of hamstrings)
Extension of thigh at hip AND flexion of knee
origin on ischial tuberosity
Semitendinosus
(part of hamstrings)
Extension of thigh at hip AND flexion of knee
origin on ischial tuberosity
Semimembranosus
(part of hamstrings)
Extension of thigh at hip AND flexion of knee
origin on ischial tuberosity
Quadriceps femoris
Extend leg at knee
Four heads are
Rectus femoris
Vastus lateralis
Vastus medialis
Vastus intermedius
Sartorius
Flexes thigh, rotates thigh laterally, flexes leg
Extensor digitorum longus
Extends toes
Gastrocnemius
inserts via Achilles tendon/calcaneal tendon on calcaneus
Plantar flexion of foot
Soleus
Plantar flexion of foot
inserts via Achilles tendon/calcaneal tendon on calcaneus. Deep to Gastrocnemius
Tibialis anterior
Dorsiflexion of foot
gluteus maximus
largest of three gluteal muscles
chief extensor of the thigh
laterally rotates the thigh
gluteus medius and minimus
deep to the gluteus maximus
abducts and medially rotates thigh
