Comp. Vert Part I

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  1. Sternocleidomastoid: breastbone-clavicle-mastoid process

    Action: prime mover of active head flexion; individually each muscle rotates head towards the shoulder on opposite side
    • O: manubrium of sternum and medial portion of clavicle
    • I: mastoid process and superior nuchal line of occipital bone
  2. scalenus: uneven
    anterior, middle, posterior 

    Action: elevates first two ribs (respiration); flexes and rotates neck
    • O: transverse process of cervicle vertebrae 
    • I: anterolaterally (front & side) on first two ribs
  3. splenius: 
    capitus (head), cervicis (neck)

    Action: act as a group to extend of hyperextend the head; when one side, head is rotated and bent laterally towards same side
    • O: nuchal ligament and spinous processes of C7-T6 vertebrae
    • I: mastoid process and transverse processes of C2-C4 vertebrae
  4. Erector spinae: 

    Action: helps control action of bending forward; act as powerful extensors to return to erect position; during full flexion (fingers to floor) erector spinae are relaxed
    • Iliocostalis
    • Longissimus
    • Spinalis
  5. Iliocoastalis: rib
    lumborum, thoracis, cervicis

    Action: extend vertebral column; acting on one side, bends vertebral column to same side
    • O: iliac crest (lumborum); inferior 6 ribs (thoracis); ribs 3-6 (cervicis)
    • I: angles of ribs (lumborum, thoracis); transverse processes of cervical vertebrae C6-C4 (cervicis)
  6. Longissimus:
    thoracis, cervicis, capitis

    Action: thoracis and cervicis act together to extend vertebral column, or on one side to laterally bend; capitis extends head and turns the face toward same side
    • O: transverse process of lumbar through cervical vertebrae
    • I: transverse processes of thoracic or cervical vertebrae and to ribs superior to origin; capitis inserts to mastoid process
  7. Spinalis:
    thoracic, cervicis

    Action: extends vertebral column
    • O: spines of upper lumbar and lower thoracic vertebrae
    • I: spines of upper thoracic and cervical vertebrae
  8. Semispinalis
    thoracis, cervicis, capitis

    Action: extends vertebral column and head and rotates them to opposite side; acts synergistically with sternocleidomastoid muscles of opposite side
    • O: transverse processes of C7-T12
    • I: occipital bone (capitis); spinous processes of cervical vertebrae (cervicis); thoracic vertebrae T1-T4 (thoracis)
  9. Quadratus lumborum: foursided-lumbar region

    Action: flexes vertebral column laterally when acting separately; when paired, lumbar spines is extended and 12th rib is fixed; maintains upright posture
    • O: iliac crest and lumbar fascia
    • I: transverse processes of upper lumbar vertebrae and lower margin of 12th rib
  10. External intercostals: toward the outside- between rib

    Action: pulls ribs toward one another to elevate rib cage; aids in respiration; synergist to diaphragm
    • O: inferior border of rib above
    • I: superior border of rib below
  11. Internal intercostals: toward the inside- between ribs

    Action: aids in drawing ribs together and forced respiration; antagonist to external intercostals
    • O:  superior border of rib below
    • I: inferior border of rib above
  12. Diaphragm: across-partition

    Action: prime mover of inspiration
    • O: inferior, internal surface of rib cage and sternum, costal cartilages of last six ribs and lumbar vertebrae
    • I: central tendon
  13. Rectus abdominus: straight-abdomen 

    Action: flex and rotate lumbar region of vertebral column; fix and depress ribs; stabilize pelvis during walking
    • O:  pubic crest and symphysis
    • I: xiphoid process and costal cartilages of ribs 5-7
  14. External oblique: toward outside- running at an angle

    Action: pair contracts to aid in flexion of vertebral column; individually aid back muscles in trunk rotation/ lateral flexion
    • O: by fleshy strips from outer surfaces of lower eight ribs
    • I: most fibers insert anteriorly into linea alba, some onto pubic crest, pubic tubercle, and iliac crest
  15. Internal oblique: deep- running at an angle

    Action: flexing vertebral column; aid muscles of back in trunk rotation and lateral flexion
    • O: lumbar fascia, iliac crest, and inguinal ligament
    • I: linea alba, pubic crest, last 3-4 ribs, and costal margin
  16. Transversus abdominus: running straight across- abdomen 

    Action: compresses abdominal contents
    • O: inguinal ligament, lumbar fascia, cartilages of last 6 ribs; iliac crest
    • I:  linea alba, pubic crest
  17. Pectoral minor: chest- lesser

    Action: draws scapula forward and downward with ribs fixed; with scapula fixed, draws rib cage superiorly
    • O: anterior surfaces of ribs 3-5 or 2-4
    • I:  coracoid process of scapula
  18. Serratus anterior: saw

    Action: prime mover to protract and hold scapula against chest wall; rotates scapula to move laterally and upward; important role in abduction and raising of arm
    • Oa series of muscle slips from ribs 1-8 (or 9)
    • I: entire anterior surface of vertebral border of scapula
  19. Subclavius: beneath-clavicle 

    Action: helps stabilize and depress pectoral girdle
    • O: costal cartilage of rib 1
    • I: groove on inferior surface of clavicle
  20. Trapezius: irregular four-sided figure

    Action: stabilizes, raises, retracts, and rotates scapula; middle fibers retract  (adduct) scapula; superior fibers elevate or extend head when scapula is fixed; inferior fibers depress
    • O: occipital bone, nuchal ligament, and spines of C7 and all thoracic vertebrae
    • I: a continuous insertion along acromion and spine of scapula and lateral third of clavicle
  21. Levator scapulae: raises- scapula 

    Action: elevates adducts scapula in concert with superior fibers of trapezius
    • O: transverse processes of C1-C4
    • I: medial border of scapula, superior to the spine
  22. Rhomboids: diamond shaped 
    major, minor

    Action: retracts scapula- squaring shoulders; stabilizes scapula
    • O: spinous processes of C7 and T1 (minor); spinous processes of T2-T5 (major)
    • I: medial border of scapula
  23. Pectoralis major: chest- larger

    Action: prime mover of arm flexion; rotates arm medially; adducts arm against resistance; pulls ribcage upward to aid in forced respiration
    • O: sternal end of clavicle, sternum cartilage of ribs 1-6 (or 7), and aponeurosis of external oblique muscle
    • I: fibers converge to insert by a short tendon into intertubercular groove of humerus
  24. Latissimus dorsi: widest- back

    Action: prime mover of arm extension; arm adductor; medially rotates arm at shoulder; depresses scapula
    • O: indirect attachment via lumbodorsal fascia into spines of lower six thoracic vertebrae, lumbar vertebrae, lower ribs 3-4, and iliac crest
    • I: spirales around teres major to insert in floor of intertubercular groove of humerus
  25. Deltoid: triangular

    Action: prime mover of arm abduction; when all fibers are active- antagonist to pectoralis major and latissimus dorsi; when anterior fibers are active acts in flexion and medial rotation of humerus therefore synergist to pectoralis major; posterior fibers effects extension and lateral rotation of arm
    • O: embraces insertion of trapezius: lateral third of clavicle; acromium and spine of scapula
    • I: deltoid tuberosity of humerus
  26. Subscapularis: under- scapula

    Action: chief medial rotator of humerus; stabilizes shoulder joint
    • O: subscapular fossa of scapula 
    • I:  lesser tubercle of humerus
  27. Supraspinatus: above- spine

    Action: stabilizes shoulder joint; assists in abduction of arm
    • O: supraspinous fossa of scapula
    • I: superior part of greater tubercle of humerus
  28. Infraspinatous: below- spine

    Action: stabilizes shoulder joint; rotates humerus laterally
    • O: infraspinous fossa of scapula
    • I: greater tubercle of humerus
  29. Teres minor: round- lesser

    Action: stabilizes shoulder joint; rotates humerus laterally; adducts arm
    • O: lateral border of dorsal scapular surface 
    • I: greater tubercle of humerus
  30. Teres major: round- greater

    Action: posteromedially extends, medially rotates, and adducts humerus; synergist of latissimus dorsi
    • O: posterior surface of scapula at inferior angle 
    • : intertubercular groove of humerus; insertion tendon fused with that of latissumus dorsi
  31. Coracobrachialis: arm

    Action: flexion and adduction of the humerus; synergist of pectoralis major
    • O: coracoid process of scapula
    • I: medial surface of humerus shaft
Card Set:
Comp. Vert Part I
2014-10-01 22:19:17
anatomy muscles
Muscles; origins, insertions, and actions
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