Anatomy 10AUnit 3: Muscles
For your practicum, you will need to know the muscle name action.O = origin; I = insertion
Muscles of head and neck:
Muscles of facial expression:
FrontalisWrinkles foreheadO: epicranial aponeurosisI: skin of eyebrow & bridge of nose
Elevates eyebrow
Corrugator superciliiDraws eyebrow to midlineO: orbital rim of frontal bone near frontonasal sutureI: eyebrow
Orbicularis oculiCloses eyeO: medial margin of orbitI: skin around eyelids
Orbicularis orisCompresses, purseslipsO: maxilla & mandibleI: lips
BuccinatorCompresses cheekO: lateral alveolar processes of maxilla & mandibleI: orbic. oris fibers
Zygomaticus majorElevates corner of mouth (smiling)O: inferior surface of zygomatic boneI: angle of mouth
Risorius Draws corner of mouth laterallyO: fascia around parotid glandI: angle of mouth
Mentalis Elevates &protrudes lower lip (pout)O: incisive fossa of mandibleI: skin of chin
PlatysmaDepresses mandible and tenses neck skinO: fascia of superior thoraxI: mandible & cheek skin
Muscles of mastication:
MasseterElevates mandiblecloses jawO: zygomatic archI: lateral surface & mandibular ramus angle
TemporalisElevates mandible& closes jawO: temporal lines of skullI: coronoid process of mandible
Anterior muscles of the neck:
SternocleidomastoidRotates head, flexes neckO: sternal end of clavicle & manubriumI: mastoid region & sup. nuchal line
Posterior muscles of the neck:
TrapeziusExtends neck, moves scapula*O: occipital bone & ligamentum nuchae *I: acromion & scapular spine
Suprahyoid muscles:
DigastricOpens mouth, elevates hyoid (larynx)O: posterior chin & mastoid of temporal boneI: hyoid
MylohyoidElevates hyoid and floor of mouthO: medial mandibleI: median CT band (raphe) to hyoid
GeniohyoidOpens mouth, elevates hyoid (larynx)O: posterior chinI: hyoid
StylohyoidElevates hyoid (larynx)O: styloid process of temporal boneI: hyoid
Infrahyoid muscles:
SternohyoidDepresses hyoid (larynx)O: clavicle & manubriumI: hyoid
SternothyroidDepresses thyroid cartilage (larynx)O: manubrium & 1st costal cartilageI: thyroid cartilage
ThyrohyoidDepresses hyoid bone, elevates larynxO: thyroid cartilageI: hyoid
Muscles of the body wall:
Thorax:
External intercostalsElevates ribs (inspiration)O: inferior border of ribI: superior border of next lower rib
Internal intercostalsDepresses ribs (expiration)O: superior border of ribI: inferior border of next upper rib
Abdomen:
Rectus abdominisFlexes vertebral column, compresses abdomenO: superior pubisI: inferior rib cartilages & xiphoid
External obliqueCompresses abdomen, trunk rotation opposite side O: inferior borders ribs 5-12 I: linea alba & iliac crest
Internal obliqueCompresses abdomen, trunk rotation same sideO: thoracolumbar fascia & iliac crest
I: inferior borders ribs 9-12, costal cartilages 8-10, linea alba, pubis
Transversus abdominisCompresses abdomen O: cartilages of ribs 6-12, iliac crest, thoracolumbar fasciaI: linea alba, pubis
Muscles of posterior thorax:
Serratus anteriorProtacts shoulder, rotates scapula up O: anterior borders of ribs 1-8I: anterior vertebral border of scapula
Levator scapulaeElevates scapulaO: transverse processes of C1-C4I: superior vertebral border of scapula
Rhomboideus majorAdducts & rotates scapula downO: spinous processes of T1-T6I: mid & lower vertebral border
Rhomboideus minorAdducts & rotates scapula downO: spinous processes of C7-T1I: mid vertebral border of scapula
TrapeziusElevates, retracts, depresses or rotates scapula upO: spinous processes of T1-T12 I: acromion & scap. spine
(adding to listing in posterior neck)
Muscles that move the arm:
Pectoralis majorFlexes, adducts, and rotates shoulder mediallyO: cart. of ribs 2-6, sternum, inferior & medial clavicle
I: greater tubercle & intertubercular groove
Pectoralis minorDepresses and protracts scapulaO: anterior ribs 3-5I: coracoid process of scapula
DeltoidAbducts shoulderO: clavicle & acromion & spine of scapulaI: deltoid tuberosity of humerus
Latissimus dorsiExtends, adducts, and rotates shoulder mediallyO: spinous processes of lower T, all L, sacrum, ribs 8-12,
and thoracolumbar fasciaI: intertubercular groove
Teres majorExtends and rotates shoulder mediallyO: inferior angle of scapulaI: intertubercular groove
Teres minorAdducts and rotates shoulder laterallyO: lateral border of scapulaI: greater tubercle of humerus
Muscles that move the forearm:
Biceps brachiiFlexes elbow & shoulderO: coracoid process, supraglenoid tubercle (scapula)I: radial tuberosity
BrachialisFlexes elbowO: distal ½ of anterior humerusI: ulnar tuberosity & coronoid process
BrachioradialisFlexes elbowO: ridge superior to lateral epicondyle of humerusI: lateral styloid process of radius
Pronator teresPronates forearm & flexes elbowO: medial epicondyle of humerus, coronoid process of ulna
I: middle of lateral surface of radius
SupinatorSupinates forearmO: lateral epicondyle of humerus & ridge near radial notch of ulna
I: anterolateral surface of radius distal to radial tuberosity
Triceps brachiiExtends elbowO: superior, lateral margin of humerus, infraglenoid tubercle of scapula, posterior
HumerusI: olecranon of ulna
Muscles that move the hand/fingers:
Flexor carpi radialisFlexes and abducts wristO: medial epicondyle of humerusI: bases of 2nd & 3rd metacarpals
Flexor carpi ulnarisFlexes and adducts wristO: medial epicondyle of humerus, adjacent medial olecranon & anteromed. ulna
I: pisiform, hamate, and base of 5th metacarpal
Palmaris longusFlexes wristO: medial epicondyle of humerusI: palmar aponeurosis & flexor retinaculum
Extensor carpi radialis longusExtends and abducts wristO: lateral supracondylar ridge of humerusI: base of 2nd metacarpal
Extensor carpi ulnarisExtends and adducts wristO: lateral epicondyle of humerus, adjacent dorsal surface of ulna
I: base of 5th metacarpal
Extensor digitorumExtends wrist and digitsO: lateral epicondyle of humerusI: posterior surfaces of phalanges 2-5
Muscles that move the thigh:
Gluteals:
Gluteus maximusExtends and rotates hip laterallyO: iliac crest, posterior gluteal line, lateral ilium, sacrum, coccyx, and
Thoracolumbar fasciaI: iliotibial tract & gluteal tuberosity femur
Gluteus mediusAbducts and rotates hip mediallyO: anterior iliac crest, lateral iliumI: greater trochanter of femur
Gluteus minimusAbducts and rotates hip mediallyO: lateral iliumI: greater trochanter of femur
Tensor fasciae lataeAbducts and rotates hip medially, extends & laterally rotates knee, tenses fasciae latae
O: iliac crest & lateral anterior superior iliac spineI: iliotibial tract
Adductors:
Adductor longusFlexes, adducts, and rotates hip mediallyO: inferior ramus of pubisI: linea aspera of femur
Adductor brevisFlexes and adducts hipO: inferior ramus of pubisI: linea aspera of femur
Adductor magnusAdducts, flexes and rotates hip medially (anterior), extension of hip (posterior)
O: inferior ramus & ischial tuberosityI: linea aspera & adductor tubercle femur
Muscles that move the leg:
Knee Flexors =”Hamstrings”:
GracilisFlexes & medial rotates knee, adducts & medially rotates hipO: inferior ramus of pubis
I: medial tibial inferior to medial condyle
SartoriusFlexes knee and hip, abducts and rotates hip laterallyO: anterior superior iliac spine
I: medial tibia near tuberosity
Biceps femorisFlexes knee, extends and laterally rotates hipO: ischial tuberosity, linea aspera
I: head of fibula, lateral condyle of tibia
SemimembranosusFlexes knee, extends and medially rotates hipO: ischial tuberosityI: posterior medial condyle of tibia
SemitendinosusFlexes knee, extends and medially rotates hipO: ischial tuberosityI: proximal, medial tibia
Knee Extensors = “Quadriceps”:
Rectus femorisExtends knee and flexes hipO: anterior inferior iliac spine & superior acetabular rim
I: tibial tuberosity, patella, and patellar ligament
Vastus medialisExtends kneeO: linea asperaI: same
Vastus lateralisExtends kneeO: anterior & inferior to greater trochanter & linea aspera (proximal ½ )I: same
Vastus intermediusExtends kneeO: anterolateral femur & linea aspera (distal ½)I: same
Muscles that move the foot/toes:
Muscles that move the foot:
GastrocnemiusPlantar flexes ankle, flexes kneeO: femoral condylesI: calcaneus via calcaneal tendon
SoleusPlanter flexes ankleO: head & prox. shaft fibula and adjacent posteromedial shaft tibia I: same
Peroneus (fibularis) longusPlanter flexes ankle and everts foot O: head & prox. shaft fibula I: base of 1st metatarsal & cuneiform 1
Peroneus (fibularis) brevisPlantar flexes ankle and everts foot O: midlateral fibulaI: base of 5th metatarsal
Peroneus tertiusDorsiflexes and everts foot
Tibialis anteriorDorsiflexes ankle, inverts foot O: lateral condyle & prox. shaft tibia I: base of 1st metatarsal & cuneiform I
Flexor digitorum longusFlexes toes 2-5, plantar flexes ankleO: posteromedial tibiaI: inferior distal phalanges 2-5
Extensor digitorum longusExtends toes 2-5, dorsiflexes ankleO: lateral condyle tibia, anterior fibulaI: superior phalanges 2-5
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