Trunk Muscle Table

Question 1

Platysma

Answer 1

O: Skin over edge of mandible
I: Skin over clavicles
I: Facial Nerve (CN VII)
A: Tenses skin on neck

*Superficial layer. Runs from mouth and mandible to 2nd rib. Attaches to fascia and skin

Question 2

Orbicularis Oris

Answer 2

I: Facial n. (CN VII)
A: Purses Lips

*Superficial Layer

Question 3

Orbicularis Oculi

Answer 3

I: Facial n. (CN VII)
A: Closes eyelids
*Superficial layer

Question 4

Zygomaticus Major & Minor

Answer 4

I: Facial n. (CN VII)
A: Smiling
*Superficial layer

Question 5

Levator Labii Superioris

Answer 5

I: Facial n. (CN VII)
A: Elevates upper lip
*Superficial layer

Question 6

Risorius

Answer 6

I: Facial n. (CN VII)
A: Smiling
*Superficial layer

Question 7

Depressor Anguli Oris

Answer 7

I: Facial n. (CN VII)
A: Depresses angle of mouth
*Superficial layer

Question 8

Levator Anguli Oris

Answer 8

I: Facial n. (CN VII)
A: Lifts angle of mouth
*Deep Layer

Question 9

Depressor Labii Inferioris

Answer 9

I: Facial n. (CN VII)
A: Depresses lower lip
*Deep layer

Question 10

Mentalis

Answer 10

I: Facial n. (CN VII)
A: Wrinkles chin, protrudes lower lip
*Deep layer

Question 11

Buccinator

Answer 11

I: Facial n. (CN VII)
A: Sucking, whistling
*Deep layer

Question 12

Superior, Anterior, and Posterior Auricular Muscles

Answer 12

I: Facial n. (CN VII)
A: Wiggle ears

Question 13

Frontalis

Answer 13

I: Facial n. (CN VII)
A: (1) Elevates eyebrows, (2) Wrinkles forehead

Question 14

Occipitalils

Answer 14

I: Facial n. (CN VII)
A: Pulls scalp back

Question 15

Longus Capitis

Answer 15

O: Transverse processes of mid-cervical vertabrae
I: Occipital bone
I: Segmental cervical ventral rami
A: Flexes head and neck

Question 16

Longus Colli

Answer 16

O: (1) Vertical portion: Lower cervical vertebrae, (2) Upper oblique portion: upper cervical bodies, (3) Lower oblique portion: lower cervical bodies

I: (1) Vertical portion: Upper cervical vertebrae, (2) Upper oblique portion: Mid-cervical transverse processes, (3) Lower oblique portion: Mid-cervical transverse processes

I: Segmental ventral rami
A: Flexlels neck

*Fibers of vertical and lower oblique portions run upward. Fibers of upper oblique portion run downward

Question 17

Rectus Capitis Anterior

Answer 17

O: Atlas
I: Occipital bone
I: Ventral rami C1, C2
A: Flexes head

Question 18

Rectus Capitis Lateralis

Answer 18

O: Atlas
I: Occipital bone
I: Ventral rami C1, C2
A: Lateral flexion of head

Question 19

Anterior Scalane

Answer 19

O: Transverse processes of mid-cervical vertebrae
I: 1st rib
I: Ventral rami of cervical nerves
A: (1) Raises 1st rib, (2) Laterally flexes neck

Question 20

Middle Scalene

Answer 20

O: All cervical transverse processes
I: 1st rib
I: Ventral rami of cervical nerves
A: (1) Raises first rib, (2) Laterally flexes neck

Question 21

Posterior Scalene

Answer 21

O: Transverse processes of mid-cervical vertebrae
I: 2nd rib
I: Ventral rami of cervical nerves
A: (1) Raises 2nd rib, (2) Laterally flexes neck

Question 22

Sternocleidomastoid

Answer 22

O: (1) Manubrium, (2) Medial 1/3 of clavicle
I: Mastoid process
I: Accessory nerve (CN XI)
A: (1) Flexes neck, (2) Rotates head to opposite side

Question 23

Digastric

Answer 23

O: (1) Posterior belly: Mastoid process, (2) Anterior belly: Inner mandible just lateral to midline.
I: Hyoid bone
I: (1) Posterior belly: facial nerve (CN VII), (2) Anterior belly: trigeminal nerve (CN V3)
A: (1) Moves hyoid superiorly and posteriorly in swallowing, (2) opens jaw against resistance

Question 24

Omohyoid

Answer 24

O: (1) Inferior belly: superior margin of scapula, (2) Superior belly: Hyoid
I: Intermediate tendon attaches to posterior clavicle and 1st rib by fascial slig
I: Branches of ansa cervicalis
A: Strap muscles as a group depress larynx, hyoid bone, and floor of mouth during swallowing
*Strap muscle

Question 25

Sternohyoid

Answer 25

``` O: Manubrium I: Hyoid bone I: Branches of ansa cervicalis A: Strap muscles as a group depress larynx, hyoid bone, and floor of mouth during swallowing *Strap muscle ```

Question 26

Sternothyroid

Answer 26

``` O: Manubrium I: Thyroid cartilage I: Branches of ansa cervicalis A: Strap muscles as a group depress larynx, hyoid bone, and floor of mouth during swallowing *Strap muscle ```

Question 27

Thyrohyoid

Answer 27

O: Thyroid cartilage I: Hyoid bone I: C1 fibers that run with hypoglossal nerve (CN XII) A: Strap muscles as a group depress larynx, hyoid bone, and floor of mouth during swallowing *Strap muscle

Question 28

Masseter

Answer 28

O: Zygomatic arch I: Ramus of mandible I: Mandibular divison of CN V (V3) A: (1) Closes mandible, (2) Protracts mandible, (3) Deep fibers retract mandible

Question 29

Temporalis

Answer 29

O: Temporal fossa I: Coronoid process of mandible I: Mandibular division of CN V (V3) A: (1) Closes mandible, (2) Retracts mandible, (3) Abduct towards side of abduction

Question 30

Lateral Pterygoid

Answer 30

O: Lateral pterygoid plate (lateral surface) I: (1) Neck of mandible, (2) TM Joint capsule, (3) Articular disc I: Mandibular division of CN V (V3) A: (1) Opens mandible, (2) Protracts mandible, (3) Protracts during abduction (opposite side of abduction)

Question 31

Medial Pterygoid

Answer 31

O: Lateral pterygoid plate (medial surface) I: Ramus of mandible, inner surface I: Mandibular division of CN V (V3) A: Closes mandible

Question 32

External intercostals

Answer 32

O: Inferior border of upper rib I: Superior border of lower rib I: Intercostal nerves A: Elevates ribs for inhalation * Runs between adjacent ribs from the tubercle of the rib as far forward as costochondral junction * Anteriorly, external intercostal membrane continues to sternum * Fibers run downward and forward

Question 33

Internal Intercostals

Answer 33

O: Inferior border of upper rib I: Superior border of lower rib I: Intercostal nerves A: Depresses ribs for exhalation * Fibers run downward and backward * Run from costal angle to sternum (incomplete posteriorly) * Continues posteriorly as the internal intercostal membrane

Question 34

Innermost Intercostals

Answer 34

O: Superior border of lower rib I: Inferior border of upper rib I: Intercostal nerves A: NONE * Less developed than the external and internal intercostals * Runs in same direction as internal intercostals (downward and backward) * Found only in the middle section of the intercostal space (Costal angle to costochondral junction) * Nerves and vessels run between innermost and internal intercostal

Question 35

Subcostal

Answer 35

O: Posterior rib I: Posterior rib I: Intercostal nerves A: None * On inner surface of posterior thorax * Fibers cross 2 or 3 ribs

Question 36

Transversus Thoracis

Answer 36

O: Sternum I: Costal cartilage I: Intercostal nerves A: Maintains thoracic wall during inspiration * On inner surface of anterior thorax * Fibers cross 2 or 3 ribs * Helps to secure blood vessels

Question 37

External Abdominal Oblique

Answer 37

O: Slips from lower 8 ribs I: (1) Aponeurosis fuses at linea alba (continues to rectus sheath), (2) Iliac crest, (3) ASIS, (4) Pubic tubercle, (5) Pubic crest, (6) Pubic symphysis I: Segmental innervation by T7-T12 or L1 A: Same as Internal Abdominal Oblique and Transversus Abdominus & Rectus Abdominus: (1) Add strength to abdominal wall because of various fiber directions, (2) Protection of abdominal contents, (3) Hold in abdominal contents, (4) Support posture - lumbar stabilization especially via transverses abdominus and attachment to thoracolumbar fascia, (5) Forced expiration, (6) Bowel movement - muscles compress abdominal contents, (7) Movement of trunk: (A) Simple flexion: all muscles involved, especially rectus abdominus, (B) Pelvic tilts, (C) Oblique flexion or rotation: internal oblique on one side and external oblique on other side work together * Interdigitates with serratus anterior * Fibers run medially and downward * Lower free edge forms inguinal ligament (ASIS to pubic tubercle)

Question 38

Internal Abdominal Oblique

Answer 38

O: (1) Thoracolumbar fascia, (2) Iliac Crest I: (1) Lower 3 or 4 ribs and costal cartilages, (2) Linea alba I: Segmental innervation by T7-T12 or L1 A: SAME as External Abdominal Oblique, Transversus Abdominus & Rectus Abdominus: (1) Add strength to abdominal wall because of various fiber directions, (2) Protection of abdominal contents, (3) Hold in abdominal contents, (4) Support posture - lumbar stabilization especially via transverses abdominus and attachment to thoracolumbar fascia, (5) Forced expiration, (6) Bowel movement - muscles compress abdominal contents, (7) Movement of trunk: (A) Simple flexion: all muscles involved, especially rectus abdominus, (B) Pelvic tilts, (C) Oblique flexion or rotation: internal oblique on one side and external oblique on other side work together *Fibers run medially and upward

Question 39

Transversus Abdominus

Answer 39

O: (1) Thoracolumbar fascia, (2) Inner surface of costal cartilages, (3) Iliac crest I: Linea alba I: Segmental innervation by T7-T12 or L1 A: Same as Internal & External Abdominal Obliques & Rectus Abdominus: (1) Add strength to abdominal wall because of various fiber directions, (2) Protection of abdominal contents, (3) Hold in abdominal contents, (4) Support posture - lumbar stabilization especially via transverses abdominus and attachment to thoracolumbar fascia, (5) Forced expiration, (6) Bowel movement - muscles compress abdominal contents, (7) Movement of trunk: (A) Simple flexion: all muscles involved, especially rectus abdominus, (B) Pelvic tilts, (C) Oblique flexion or rotation: internal oblique on one side and external oblique on other side work together *Fibers run horizontally

Question 40

Rectus Abdominus

Answer 40

O: (1) Xiphoid process, (2) Costal cartilages of ribs 5-7 I: (1) Pubic crest, (2) Pubic tubercle I: Segmental innervation by T7-T12 or L1 A: Same as EAO, IAO, and Transversus Abdominus: (1) Add strength to abdominal wall because of various fiber directions, (2) Protection of abdominal contents, (3) Hold in abdominal contents, (4) Support posture - lumbar stabilization especially via transverses abdominus and attachment to thoracolumbar fascia, (5) Forced expiration, (6) Bowel movement - muscles compress abdominal contents, (7) Movement of trunk: (A) Simple flexion: all muscles involved, especially rectus abdominus, (B) Pelvic tilts, (C) Oblique flexion or rotation: internal oblique on one side and external oblique on other side work together *Fibers run vertically

Question 41

Splenius Cervicis

Answer 41

O: Spinous processes T3-T6 I: Transverse processes C1-C3 I: Dorsal rami A: (1) Extends neck (bilateral contraction), (2) Rotates head to same side (unilateral contraction)

Question 42

Splenius Capitis

Answer 42

O: (1) Spinous processes C7-T4, (2) Ligamentum nuchae I: (1) Mastoid process, (2) Lateral part of superior nuchal line I: Dorsal rami A: (1) Extends neck (bilateral contraction), (2) Rotates head to same side (unilateral contraction)

Question 43

Erector Spinae Iliocostalis: (A) Lumborum (B) Thoracis (C) Cervicis

Answer 43

O: (A)Lumborum (common origin): (1) Iliac Crest, (2) Sacrum, (3) Spinous processes of T11-T12, (4) Lumbar vertebrae. (B) Thoracis: Lower ribs (C) Cervicis: Upper ribs I: (A) Lumborum: lower ribs (B) Thoracis: upper ribs insertion (C) Cervicis: cervical transverse processes I: Dorsal rami A: (1) Extends back (bilateral contraction, (2) Lateral flexion of trunk (unilateral contraction), (3) Controls flexion eccentrically against gravity *Most lateral portion of erector spinae

Question 44

Erector Spinae Longissimus: (A) Thoracis (B) Cervicis (C) Capitis

Answer 44

O: (A) Thoracis (common origin): (1) Iliac Crest, (2) Sacrum, (3) Spinous processes of T11-T12, (4) Lumbar vertebrae. (B) Cervicis: Upper 4-6 thoracic transverse processes (C) Capitis: Upper cervical transverse processes I: (A) Thoracis: Lateral ribs and thoracic transverse processes (B) Cervicis: cervical 2-6 processes (C) Capitis: mastoid process I: Dorsal rami A: (1) Extends back (bilateral contraction, (2) Lateral flexion of trunk (unilateral contraction), (3) Controls flexion eccentrically against gravity *Intermediate portion of erector spinae

Question 45

Erector Spinae Spinalis

Answer 45

O: Lower thoracic spinous processes I: Upper thoracic spinous processes I: Dorsal Rami A: (1) Extends back (bilateral contraction, (2) Lateral flexion of trunk (unilateral contraction), (3) Controls flexion eccentrically against gravity *Only well-developed in thoracic region

Question 46

Semispinalis: (A) Thoracis (B) Cervicis (C) Capitis

Answer 46

O: (A & B) Thoracis and Cervicis: Transverse processes at appropriate level (C) Capitis: Lower cervical transverse processes I: (A&B) Thoracis and Cervicis: Spinous processes at appropriate level (C) Capitis: Space between superior and inferior nuchal lines I: Dorsal Rami A: Rotation to the opposite side * Transversospinalis muscles * Well-developed in cervical area, not seen in lumbar area * Lie deep to and are shorter than erector spinae fibers * Thoracic and cervicis fibers cross 4-6 segments * Thoracis and cervicis run upward from lateral to medial (transverse process to spinous process) * Capitis fibers run vertically

Question 47

Multifidus

Answer 47

O: Transverse processes I: Spinous processes I: Dorsal rami A: Rotation to opposite side * Transversospinalis muscles * Lie deep to and are shorter than erector spinae fibers * Cross 2-4 segments up to C2 * Well-developed in lumbar region and easily seen there b/c there is no semispinalis in lumbar * Run upward from lateral to medial (transverse process to spinous process)

Question 48

Rotators

Answer 48

O: Transverse processes I: Spinous processes I: Dorsal rami A: Rotation to opposite side * Transversospinalis muscles * Lie deep to and are shorter than erector spinae fibers * Cross 1 (short) to 2 (long) segments * Run upward from lateral to medial (transverse process to spinous process)

Question 49

Segmental muscles: (A) Interspinales (B) Intertransversarii

Answer 49

O: Across adjacent vertebrae on either transverse process or deep I: NONE I: Dorsal rami A: Extends from one vertebra to the next * Only found in cervical and lumbar regions * Will NOT see in lab

Question 50

Obliquus Capitis Inferior

Answer 50

O: Spinous process of axis I: Transverse process of atlas I: Suboccipital nerve (C1) A: Rotates atlas and head to same side * Suboccipital muscles * Connect atlas and axis to each other and to the skull

Question 51

Obliquus Capitis Superior

Answer 51

O: Transverse process of atlas I: Near inferior nuchal line I: Suboccipital nerve (C1) A: (1) Extends neck (bilateral contraction), (2) Lateral flexion of neck (unilateral contraction) * Suboccipital muscles * Connect atlas and axis to each other and to the skull

Question 52

Rectus Capitis Posterior Major

Answer 52

O: Spinous process of axis I: Inferior nuchal line under middle I: Suboccipital nerve (C1) A: Extends neck (bilateral contraction) * Suboccipital muscles * Connect atlas and axis to each other and to the skull

Question 53

Rectus Capitis Posterior Minor

Answer 53

O: Posterior tubercle of atlas I: Partially under cover of Rectus Capitis Posterior Major near inferior nuchal line I: Suboccipital nerve (C1) Extends neck (bilateral contraction) * Suboccipital muscles * Connect atlas and axis to each other and to the skull