Muscle System Flashcards
Epicranius (occipitofrontalis) frontal belly
Covers forehead and dome of skull – no bony attachments
O: epicranial aponeurosis
I: face skin eyebrows Fixes aponeurosis and raises eyebrows (surprise) – wrinkles forehead horizontally
Epicranius (occipitofrontalis) Occipital belly
By pulling on the epicranial aponeurosis it fixes the origin of the frontal belly
Fixes aponeurosis and pulls scalp posteriorly
Corrugator supercilia (wrinkle eyebrow)
Small muscle associated with Orbicularis oculi
O: frontal bone
I: skin of eyebrow
Draws eyebrows medially and inferiorly angry eyebrows
Orbicularis oculi
Thin, flat muscle around eyelid
O: frontal and maxillary bones
I: skin of eyelids
Closes eye- blinking and squinting
Orbicularis oris
Complicated multilayer muscle that runs in many directions around the mouth
O: maxilla and mandible
I: skin of mouth
Closes lips: kissing and whistling
Zygomaticus
Major and minor – pair that extend from cheekbone to corner of mouth
O: zygomatic bone
I: skin of mouth
Raises lateral side of mouth - smiling
Risorius (laughter)
Razor like slender muscle inferior and lateral to Zygomaticus
O: masseter
I: skin of mouth
Draws corner of lips laterally – synergist to Zygomaticus
Levator labii superioris (raise lip above)
Thin muscle between Orbicularis oris and inferior eye margin
O: zygomatic bone and maxilla
I: upper lip
Opens lips
Depressor labii inferioris
Small
O: mandible
I: lower lip
Draws lower lip inferiorly - pout
Depressor anguli oris
Small muscle lateral to Depressor labii inferioris
O: mandible
I: skin mouth
Draws corners of mouth down (grimace) antagonist to Zygomaticus
Mentalis (chin)
Muscle pair forming V shaped mass on chin
O: mandible
I: skin of chin
Wrinkles chin; pout
Buccinator
Thin horizontal cheek muscle deep to masseter
O: maxilla and mandible
I: Orbicularis oris
Compresses cheek – whistling sucking keeps food in mouth
Platysma
Thin superficial neck muscle role in facial expression
O: chest
I: mandible and skin of mouth
Tenses skin of neck and depress mandible
Masseter (chewer)
Powerful muscle covers the lateral part of the mandibular ramus
O: zygomatic bone
I: mandible
Prime mover of jaw closure – elevates mandible
Temporalis
Fan shaped; covers the temporal, parietal, and frontal bones
O: temporal bone
I: mandible
Closes jaw or bite down
Medial pterygoid
Deep 2-headed muscle runs along internal surface of mandible
O: sphenoid bone and maxilla
I: medial surface of mandible
Acts with lateral pterygoid to protract mandible and side to side grinding
Lateral pterygoid
Deep 2-headed muscle that runs superior to medial pterygoid
O: sphenoid bone
I: mandible
protract mandible and side to side grinding
Genioglossus (chin tongue)
Fan shaped muscle that forms bulk of the inferior tongue – attachment to the mandible prevents the tongue from falling back into the throat and prevent breathing
O: mandible
I: hyoid bone
Protracts tongue – sticking out tongue
Hyoglossus (hyo = hyoid bone)
Flat quadrilateral
O: hyoid bone
Depresses tongue
Styloglossus
(stylo=styloid process)
O: styloid process of temporal bone
Retracts and elevates tongue
Digastric
Suprahyoid 2 bellies united by intermediate tendon form V shape under chin O: mandible and temporal bone I: hyoid bone Open mouth and depress mandible
Stylohyoid
suprahyoid Parallels posterior belly of digastric O: styloid process of temporal bone I: hyoid bone Elevates and retracts hyoid
Mylohyoid (molar)
suprahyoid Deep to digastric muscle – muscle pair forms floor of the anterior mouth O: mandible I: hyoid bone Elevates hyoid bone and floor of mouth
Geniohyoid (chin)
suprahyoid Deep to mylohyoid muscle O: mandible I: hyoid bone Pulls hyoid bone superiorly and anteriorly
Sternohyoid
infrahyoid
Most medial muscle of the neck thin and superficial except inferiorly where covered by sternocleidomastoid
O: manubrium and clavicle
I: hyoid bone
Depresses hyoid bone and larynx if the mandible is fixed
Sternothyroid
infrahyoid Lateral and deep to Sternohyoid O: manubrium I: thyroid cartilage Depresses larynx and hyoid bone
Omohyoid (omo=shoulder)
infrahyoid 2 bellies united by intermediate tendon lateral to Sternohyoid O: scapula I: hyoid bone Depresses and retracts hyoid bone
Thyrohyoid
infrahyoid Superior continuation of Sternothyroid O: thyroid cartilage I: hyoid bone Depresses hyoid bone and elevates larynx if the hyoid is fixed
Superior middle and inferior pharyngeal constrictor muscles
pharyngeal constrictor muscle 3 paired muscle whose fibers run circularly in pharynx wall; superior is innermost and inferior is outermost substantial overlap O: mandible, hyoid bone, larynx I: pharynx Constrict pharynx during swallowing
Sternocleidomastoid
anterolateral neck
2 headed muscle; deep to platysma
O: manubrium and clavicle
I: temporal bone (mastoid process) occipital bone Flexes and laterally rotates head
Scalenes – anterior middle and posterior
anterolateral neck Lateral on neck; deep to platysma and SCM O: cervical vertebrae I: first 2 ribs Elevate 1st 2 ribs – forced inspiration
Splenius (bandage, head, neck)
intrinsic muscle of the back
Capitus and cervicis portions
Broad bipartite superficial muscle capitus is bandage muscle because it covers and holds down deeper neck muscles
O: ligamentum nuchae; vertebrae C7-T6
I: mastoid process of temporal bone and occipital bone (capitus) and C2-C4 (cervicis)
Extend or hyperextend head – pulls to same side
Erector spinae
Prime mover of back extension; during full flexion the erector spinae are relaxed (fingers touching the floor) when reversing this movement these muscles are initially inactive – extension initiated by hamstring and gluteus max
erector spinae - Iliocostalis (ilium, rib, thorax)
Lumborum, thoracis, cervicis – most lateral group of ES
O: iliac crest (lumborum); ribs (thoracis and cervicis)
I: ribs (lumborum and thoracis) cervical vertebrae (cervicis)
Extend and laterally flex the vertebral column
erector spinae - Longissimus (longest)
Thoracis, cervicis and capitis – intermediate
O: lumbar -cervical vertebrae
I: thoracic and cervical certebrae, ribs and the capitis inserts into the temporal bone
Extend and laterally flex the vertebral column; extends head and turn face to same side (dif capitis bc inserts in temporal bone)
erector spinae - Spinalis
Thoracis and cervicis – medial
O: lumbar and thoracic vertebrae
I: thoracic and cervical vertebrae (move up)
Extends vertebral column
Semispinalis
intrinsic back muscle
Thoracis, cervicis and capitis – deep layer
O: C7-T12
I: occipital bone (capitis) cervical vertebrae (cervicis) and thoracic vertebrae (thoracis)
Extends vertebral column and head and rotates them to opposite direction
Quadratus lumborum
intrinsic back muscle Deeper- posterior abdominal wall O: iliac crest I: lumbar vertebrae Laterally flexes vertebral column and forced inspiration – pull down abdominal wall
External intercostals
thorax muscles - breathing
O: rib
Pull ribs toward each other to lift rib cage
Internal intercostals
thorax muscle - breathing
O: rib
Brings ribs together and depresses rib cage – forced expiration
Diaphragm
thorax muscle - breathing
Floor of thoracic cavity, dome shaped when relaxed key muscle for inspiration
O: rib cage, sternum and costal cartilages
I: central tendon
Prime mover of inspiration – flattens on contraction pulls down thoracic cavity and brings air in
External obliques
anterior and lateral abdominal wall
Largest and most superficial, runs downward and medially (hands in pocket) forming inguinal ligament O: ribs
I: linea alba and iliac crest
Flex vertebral column and compress abdominal wall
Rotating trunk and flexing laterally (individually)
Internal obliques
anterior and lateral abdominal wall
Fibers runs upward and medially
O: lumbar, iliac crest
I: linea alba, pubic crest, ribs
Flex vertebral column and compress abdominal wall
Rotating trunk and flexing laterally (individually) same as above
Rectus abdominus
anterior and lateral abdominal wall Medial superficial O: pubic crest I: xiphoid process and ribs Flex and rotate lumbar region of vertebral column
Transversus abdominus
anterior and lateral abdominal wall Deepest and fibers fun horizontally O: lumbar I: linea alba, pubic crest Compresses abdominal contents
Levator ani (raises anus)
pelvic diaphragm
Broad tripartite - pubococcygeus, puborectalis, iliococcygeus forms a muscular sling
O: inside pelvis
Supports and maintains positions of pelvic organs
Coccygeus
pelvic diaphragm
Small triangular muscle
O: pelvis
Supports pelvic organs
External urethral sphincter (squeeze)
urogenital diaphragm inferior to pelvic diaphragm
Muscle circling the urethra and vagina Constricts urethra
Deep transverse perineal muscle
Supports pelvic organs
urogenital diaphragm inferior to pelvic diaphragm
Ischiocavernosus
superficial perineal space
Pelvis to base of penis or clit
Maintains erection of penis or vagina stops venous drainage
Bulbospongiosus
Encloses base of penis
Empties male urethra
superficial perineal space
Superficial transverse perineal muscles
Posterior to urethral opening
Stabilizes and strengthens the central tendon of perineum
superficial perineal space
Pectoralis minor
superficial muscles of anterior thorax Beneath pectoralis major O: ribs 3-5 I: scapula Brings scapula forward and downward
Serratus anterior
superficial muscles of the anterior thorax
O: ribs 1-8
I: scapula
Rotates scapula so the inferior angle moves upward and lateral
Subclavius
superficial muscles of the anterior thorax
O: costal cartilage
I: clavicle
Stabilize and depress pectoral (shoulder) girdle
Trapezius
superficial muscles of the posterior thorax
Most superficial
O: occipital bone, C7 and thoracic vertebrae
I: scapula and clavicle
Stabilizes, elevates, rotates and retracts scapula
Levator scapulae
superficial muscles of the posterior thorax Deep to trapezius O: C1-C4 I: scapula Elevates and adducts scapula
Rhomboids
superficial muscles of the posterior thorax
Major and minor (superior); deep to trapezius and inferior to levator scapulae
O: C7 and T1 and T2-T5
I: scapula
Stabilize scapula
Pectoralis major
cross the shoulder joint moving the humerus
O: clavicle, sternum, ribs 1-6 and external obliques
I: humerus
Adducts and medially rotates arm;
clavicular part: assists in flexion when arm is extended
Sternal part: assists in extension when arm is flexed
Deltoid
cross shoulder joint move humerus
Multipennate
O: clavicle and scapula
I: humerus
Prime mover of arm abduction (all fibers active) antagonize pec maj and LD
Anterior fibers active: flexing and rotating arm medially – synergist to pec maj
Posterior fibers active: extension and lateral rotation of arm
Latissimus dorsi
cross shoulder joint move humerus
Broad flat
O: thoracic and lumbar vertebrae, ribs 3-4, iliac crest, scapula
I: humerus
Prime mover of arm extension and adduction; medially rotates arm at shoulder
Subscapularis (RC)
cross shoulder joint move humerus
O: scapula
I: humerus
Medial rotator of arm; stabilize shoulder joint and assisted by pec major
Supraspinatus (RC)
cross shoulder joint move humerus Posterior scapula deep to trapezius O: scapula I: humerus Initiates abduction of arm, stabilizes shoulder joint
Infraspinatus
cross shoulder joint move humerus Covered by deltoid and trapezius O: scapula I: humerus Rotates arm laterally; stabilizes shoulder joint
Teres minor
cross shoulder joint move humerus Inferior to Infraspinatus O: scapula I: humerus Rotates arm laterally; stabilizes shoulder joint same as infraspintus
Teres major (synergist)
cross shoulder joint move humerus Inferior to teres minor O: scapula I: humerus Extends, medially rotates and adducts arm synergist of latissimus dorsi
Coracobrachialis (Synergist)
cross shoulder joint move humerus
O: scapula
I: humerus
Flexes and adducts arm
Triceps brachii
posterior elbow joint muscle 3 headed origin long and lateral heads superficial to medial head O: long head: scapula; lateral head: humerus Medial head: humerus I: ulna Forearm extensor (prime mover by medial head) long and lateral heads active in extending the arm against resistance
Anconeus
posterior muscles of the elbow joint
O: humerus
I: ulna
Ulnar abduction during pronation stabilize arm joint
Biceps brachii
anterior muscle crossing elbow joint 2 headed origin short head and long head cross shoulder and elbow joint O: scapula I: radius Flexes and supinates arm
Brachialis
anterior muscles crossing the elbow joint
Deep to bicep on distal humerus
O: humerus
I: ulna
Forearm flexor – lifts ulna as bicep lifts radius
Brachioradialis
anterior muscle crossing the elbow joint Superficial and lateral O: humerus I: radius Synergist in flexing forearm
Pronator teres
anterior superficial muscle of the forearm 2 headed muscle O: humerus and ulna I: radius Pronates forearm
Flexor carpi radialis
anterior superficial muscle of the forearm
O: humerus
I: metacarpals Flexor and abductor of hand
Palmaris longus
anterior superficial muscle of forearm
O: humerus
I: palmaris aponeurosis
Tenses skin of palm during hand movements
Flexor carpi ulnaris
anterior superficial muscle of forearm Most medial, 2 headed O: humerus and ulna I: metacarpal Flexor and adductor of hand
Flexor digitorum superficialias
anterior superficial muscle of the forearm
2 headed muscle – more deep
O: humerus, ulna, radius
I: fingers 2-5 not thumb
Flexes wrist and middle phalanges of fingers 2-5 (fingers curl towards palm)
Flexor pollicis longus
anterior deep muscle of the forearm
O: radius
I: thumb
Flexes distal phalange of thumb
Flexor digitorum profundus
anterior deep muscle of forearm
O: ulna
I: 2-5 fingers
Flexes distal interphalangeal joints
Pronator quadratus
anterior deep muscle of the forearm Deepest muscle O: ulna I: radius Prime mover of forearm protonation
Extensor carpi radialis longus
superficial muscle of posterior forearm
Parallels brachioradialis on lateral forearm O: humerus
I: metacarpals Extends and abducts hand
Extensor carpi radialis brevis
superficial posterior muscle of forearm Shorter than longus and deeper O: humerus I: metacarpal Extends and abducts hand
Extensor digitorum
superficial posterior muscle of forearm Medial to extensor carpi radialis brevis Extensor digiti minimi O: humerus I: 2-5 fingers Prime mover of finger extension – counteracts flexor
Extensor carpi ulnaris
superficial posterior muscle of forearm Most medial O: humerus, ulna I: metacarpals Extends and adducts hand
Supinator
deep posterior muscle of forearm
Deep muscle at posterior aspect of elbow
O: humerus and ulna
I: radius
Assists bicep in forcibly supinating forearm
Abductor pollicis longus
deep muscle of posterior forearm Distal to supinator O: radius and ulna I: first metacarpal Extends and abducts thumb
Extensor pollicis brevis and longus
deep posterior of forearm Shorter than longus and deeper O: radius and ulna I: thumb Extends thumb
Extensor indices
deep muscle of posterior forearm Medial to extensor pollicis brevis and longus Extensor digiti minimi O: ulna I: index finger Extends index finger
Iliopsoas
anterior and medial crossing hip joint
Combo of iliacus and psoas major that combine in a common tendon
O: humerus and ulna
I: radius
Assists bicep in forcibly supinating forearm
iliacus and psoas major
• Iliacus
anterior and medial muscle crossing the hip joint Large more lateral
O: iliac fossa and crest
I: femur
Prime mover for flexing thigh or flexing trunk onto thigh
• Psoas major (loin large)
anterior and medial muscles crossing the hip joint
Longer thicker more medial
O: lumbar vertebrae and T12
I: femur via iliopsoas tendon
Prime mover for flexing thigh or flexing trunk onto thigh and flexes vertebral column laterally
Sartorius
anterior and medial muscle crossing the hip joint
Longest muscle in body
O: iliac spine
I: tibia
Flexes, abducts and laterally rotates thigh
Gluteus maximus
posterior pelvic muscle Largest and most superficial O: dorsal ilium, sacrum, coccyx I: femur, iliotibial tract Extensor of thigh, most effective when thigh is flexed
Gluteus medius
posterior pelvic muscle Intramuscular injections O: ilium I: femur Abducts and medially rotates thigh; walking - holds pelvis so doesn’t sag
Gluteus minimus
posterior pelvic muscles Smallest and deepest O: ilium I: femur Abducts and medially rotates thigh; walking - holds pelvis so doesn’t sag
Piriformis
lateral rotators Inferior to gluteus minimus O: sacrum I: femur Rotates extended thigh laterally and helps adduct thigh
Obturator externus
lateral rotator Superomedial aspect of thigh O: obturator foramen I: femur Rotates extended thigh laterally and helps adduct thigh
Obturator internus
lateral rotator Surrounds obturator foramen in pelvis O: obturator foramen I: greater trochanter Rotates extended thigh laterally and helps adduct thigh
Gemellus
lateral rotator Superior and inferior O: ischial spine I: femur Rotates extended thigh laterally and helps adduct thigh
Quadratus femoris
lateral rotator
Most inferior
I: femur
Rotates thigh laterally NO extension
Quadriceps femoris
4 separate heads with common insertion tendon (quadriceps tendon) inserts into patella then via patellar ligament into tibial tuberosity
anterior thigh
quadriceps femoris - • Rectus femoris
anterior thigh Superficial O: iliac spine I: patella and tibial tuberosity Extends leg and flexes thigh at hip
quadriceps femoris - Vastus lateralis
Largest head O: linea aspera femur I: patella and tibial tuberosity Extends leg and stabilizes leg anterior thigh
quadriceps femoris - Vastus medialis
anterior thigh Inferomedial aspect of thigh O: linea aspera femur I: patella and tibial tuberosity Extends leg no hip flexion bc only cross knee joint not hip joint
quadriceps femoris - Vastus intermedius
anterior thigh Intermediate O: femur shaft I: patella and tibial tuberosity Extends leg
Tensor fascia lata
anterior thigh
O: iliac crest
I: iliotibial tract (thick lateral portion or fascia lata) Steadies leg and trunk on thigh by making iliotibial tract taut
Hamstrings
posterior thigh - Cross both hip and knee joints; prime movers of thigh extension and knee flexion innervated by sciatic nerve
hamstrings- Biceps femoris
posterior thigh Most lateral; 2 heads O: ischial tuberosity (long head) Femur (short head) I: fibula and tibia Extends thigh and flexes leg
hamstrings - Semitendinosus
posterior thigh Mostly tendinous O: ischial tuberosity I: tibia Extends thigh and flexes leg
hamstring - Semimembranosus
posterior thigh Deep to semitendinosus O: ischial tuberosity I: tibia Extends thigh and flexes leg
Adductor magnus
medial thigh
O: ischial and pubic rami
I: femur
Adducts, medially rotates, flexes and extends thigh (synergist of hamstrings)
Adductor longus
medial thigh Most anterior O: pubis I: linea aspera (femur) Adducts, flexes and medially rotates thigh
• Adductor brevis
medial thigh Deep to semitendinosus O: pubic ramus I: linea aspera (femur) Adducts, flexes and medially rotates thigh
Pectineus
medial thigh
O: pubis
I: femur
Adducts, flexes and medially rotates thigh
Gracilis
medial thigh Long thin superficial O: pubis I: tibia Adducts, flexes and medially rotates leg – crosses knee joint too
Tibialis anterior
anterior calf Superficial O: tibia I: first metatarsal bone (big toe) Prime mover of dorsiflexion and inverts foot
Extensor digitorum longus
anterior calf Unipennate muscle O: tibia and fibula I: 2-5 toes Primary mover of toe extension; dorsiflexes foot
Fibularis tertius
anterior calf Not always present O: fibula I: 5th metatarsal Dorsiflexes and everts foot
Extensor hallucis longus
anterior calf Deepest O: fibula I: big toe Extends great toe; dorsiflexes foot
Fibularis longus
lateral calf Superficial, lateral O: fibula I: first metatarsal bone (big toe) Plantar flexion and everts foot
Fibularis brevis
lateral calf Deep O: fibula I: 5th metatarsal Plantar flexion and everts foot
Triceps surae - Gastrocnemius
superficial posterior calf 2 prominent bellies O: 2 heads from femur I: calcaneus Plantar flexion and flexes knee (weak at knee joint)
Triceps surae - Soleus
superficial posterior calf Deeper O: tibia and fibula I: gastrocnemius Plantar flexes foot, walking, running, dancing
Plantaris
superficial posterior calf Small, may be absent O: femur I: calcaneus Flex leg and plantar flex foot
Popliteus
deep posterior calf Inferomedial O: femur I: tibia Flexes and rotates leg medially
Flexor digitorum longus
deep posterior calf
O: tibia
I: 2-5 toes
Plantar flexion and inverts foot, flexes toes
Flexor hallucis longus
deep posterior calf bipennate O: fibula I: big toe Plantar flexion and inverts foot, flexes big toe
Tibialis posterior
deep posterior calf Deep to soleus O: tibia fibula I: metatarsals 2-4 Prime mover of foot inversion; plantar flexes
