Chapter 10-Muscles Flashcards
Mouth Region
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Buccinator
Origin: alveolar processes of maxilla and mandible opposite the molar teeth
Insertion: blens into fibers of orbicularis oris
Action: compresses cheeks
Innervation: Facial Nerve (N 8)
Mentalis
Origin: incisive fossa of mandible
Insertion: skin of chin
Action: elevates, everts and protrudes lower lip
Orbicularis Oris
Origin: Maxila and mandible
Insertion: Lips
Action: compresses, purses lips
Risorius
Origin: fascia surrounding parotid salivary gland
Insertion: angle of mouth
Action: Draws corner of mouth laterally
Zygomaticus Major
Origin: zygomatic bone near the zygomaticotemporal suture
I: angle of mouth
A: elevates corner of mouth and draws it laterally
Eye
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Orbicularis Oculi
Origin: Medial margin of orbit
Insertion: skin around eyelids
Action: closes eye
Innervation: facial nerve (N 7)
Scalp
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Occipitofrontalis: frontal belly
Origin:epicranial aponeurosis
Insertion: Skin of eyebrow and bridge of nose
Action: raises eyebrows, wrinkles forehead
Occipitofrontalis: occipital belly
Origin: superior nuchal line and adjacent region of mastoid portion of the temporal bone
Insertion: epicranial aponeurosis
Action: tenses and retracts scalp
Temporoparietalis
Origin: fascia around external ear
Insertion: epicranial aponeurosis
Action: tenses scalp, moves auricle of ear
Muscles of Mastication
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Masseter
Origin: zygomatic arch
Insertion: lateral surface and angle of mandibular ramus
Action: elevates mandible and closes jaws; assists in protracting and retracting mandible and moving mandible side to side
Innervation: trigeminal nerve (N 5), mandibular branch
Temporalis
Origin: along temporal lines of skull
Insertion: coronoid process of mandible and the anterior border of the mandibular ramus
Action: along temporal lines of skull
Anterior muscles of neck
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Digastric
Insertion: hyoid bone
Action: depresses mandible, opening mouth, and/or elevates larynx
Digastric: anterior belly
origin: from inferior surface of mandible at chin
Insertion: hyoid bone
action: presses mandible, opening mouth, and/or elevates larynx
innervation: trigeminal nerve (N 5), mandibular branch
digastric; posterior belly
origin: from mastoid region of temporal bone
insertion: hyoid bone
action: depresses mandible, opening mouth, and/or elevates larynx
innervation: facial nerve (N 7)
Geniohyoid
Origin: medial surface of mandible at chin
Insertion: hyoid bone
Action: as above and retracts hyoid bone
mylohyoid
origin: mylohyoid line of mandible
insertion: median connective tissue band that runs to hyoid bone
action: elevates floor or mouth, elevates hyoid bone, and/or depresses mandible
sternohyoid
origin: clavicle and manubrium
Insertion: hyoid bone
Action: depresses hyoid bone and larynx
Innervation: cervical spinal nerves C1-C3
sternothyroid
origin: dorsal surface of manubrium and first costal cartilage
insertion: thyroid cartilage of larynx
action: depresses hyoid bone and larynx
sternocleidomastoid: clavicular head
origin: attaches to sternal end of clavical
insertion: mastoid region of skull and lateral portion of superior nuchal line
Action: together, they flex the neck; alone one side bends neck toward shoulder and turns face to opposite side
sternocleidomastoid: sternal head
origin: attaches to sternal end of clavicle
Insertion: mastoid region of skull and lateral portion of superior nuchal line
Action: together, they flex the neck; alone one side bends neck toward shoulder and turns face to opposite side
Thyrohyoid
origin: thyroid cartilage of larynx
Insertion: hyoid bone
action: elevates larynx, depresses hyoid bone
OBLIQUE GROUP
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Thoracic region
external intercostals, internal intercostals
external intercostals
origin: inferior border of each rib
insertion: superior border of more inferior rib
Action: elevate ribs
Innervation: intercostal nerves (branches of thoracic spinal nerves)
internal intercostals
origin: superior border of each rib
insertion: inferior border of the more superior rib
action: depress ribs
Serratus posterior: inferior
origin: aponeurosis from spinous processes of T10-L3
insertion: inferior borders of ribs 9-12
action: pulls ribs inferiorly; also pulls outward, opposing diaphragm
Abdominal region
external oblique
internal oblique
transversus abdominus
external oblique
origin: external and inferior borders of ribs 5-12
insertion: external oblique aponeuroses extending to linea alba and iliac crest
action: compresses abdomen; depresses ribs; flexes, laterally flexes, or rotates vertebral column to opposite side
internal oblique
origin: thoracolumbar fascia, inguinal ligament, iliac crest
insertion: inferior surfaces of ribs 9-12, costal cartilages 8-10, linea alba, pubis
action: compresses abdomen; depresses ribs; flexes, laterally flexes, or rotates vertebral column to same side
transversus abdominus
origin: cartilages of ribs 6-12, iliac crest, and thoracolumbar fascia
insertion: linea alba and pubis
action: compresses abdomen
RECTUS GROUP
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Diaphragm
origin: xiphoid process, ribs 7-12 and associated costal cartilages, and anterior surfaces of lumbar vertebrae
insertion: central tendinous sheet
action: contraction expands thoracic cavity, compresses abdominopelvic cavity
innervation: phrenic nerves (C3-C5)
Rectus Abdominus
origin: superior surface of pubis around symphysis
insertion: inferior surfaces of cartilages (ribs 5-7) and xiphoid process of sternum
action: depresses ribs, flexes vertebral column and compresses abdomen
Pectoralis Minor
Origin: anterior surfaces and superior margins of ribs 3-5 or 2-4 and the fascia covering the associated external intercostal muscles
Insertion: Coracoid process of scapula
Action: depresses and protracts shoulder; rotates scapula so glenoid cavity moves inferiorly (downward rotation); elevates ribs if scapula is stationary
Rhomboid major
origin: ligamentum nuchae and the spinous processes of vertebrae T2 to T5
Insertion: vertebral border of scapula from spine to inferior angle
Action: adducts and performs downward rotation of the scapula
Rhomboid minor
origin: spinous processes of vertebrae C7-T1
Insertion: vertebral border of scapula
Action: adducts and performs downward rotation of the scapula
Serratus Anterior
origin: anterior and superior margins of ribs 1-8, 1-9, or 1-10
Insertion:anterior surface of vertebral border of scapula
Action: protracts shoulder; rotates scapula so glenoid cavity moves superiorly (upward rotation)
Subclavius
Origin: first rib
Insertion: Clavicle (inferior border of middle 1/3)
Action: Depresses and protracts shoulder
Trapezius
origin: occipital bone, ligamentum nuchae, and spinous processes of thoracic vertebrae
Insertion: clavicle and scapula (acromion and scapular spine)
Action: depends on active region and state of other muscles; may elevate, retract, depress, or rotate scapula upward and/or clavicle; can also extend neck when the position of the shoulder is fixed
muscles that position the pectoral girdle
pectoralis minor rhomboid major rhomboid minor serratus anterior subclavius trapezius
muscles that move the arm
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coracobrachialis
origin: coracoid process
insertion: medial margin of shaft of humerus
action: adduction and flexion at shoulder
deltoid
origin: clavicle and scapula (acromion and adjacent scapular spine)
insertion: deltoid tuberosity of humerus
action: whole muscle: abduction of shoulder; anterior part: flexion and medial rotation of humerus; posterior part: extension and lateral rotation of humerus
innervation: axillary nerve (C5-C7)