L4: Myology Of The Trunk

Question 1

is external intercostal for inhalation or exhalation? explain why based on its origin & insertion.

Answer 1

inhalation

origin: inf rib
insertion: sup rib below
thus fiber orientation is inferomedial

Question 2

the SCM expands the ___ by elevating sternum and the clavicle, which helps in inspiration

Answer 2

thoracic cavity

Question 3

Muscles used for inhalation

Answer 3

diaphgragm; External intercostal;
sternocleidomastoid;
serratus anterior & pec minor -> elevate the ribs when scapula is fixed

Question 4

action of internal intercostal due to its origin & insertion

Answer 4

exhalation

origin: sup bor. of rib
insertion: inf bor. of rib above
thus fiber orientation is superolateral

Question 5

4 intrinsic muscles of the thor wall

Answer 5

diaphragm; external, internal, & innermost intercostals

Question 6

the 3 classification of back muscles are?

Answer 6

superficial
intermediate
deep

Question 7

the back’s superficial layer are made of muscles that move the ___ while the intermediate layer are made of muscles attached to the __ and move the ___

Answer 7

shoulder girdle
ribs
thor cage

Question 8

the back’s deep layer, also known as the true back muscles, are found in the __ and can be divided into __ & ___

Answer 8

vert column

extrinsic & intrinsic

Question 9

which back muscles can move the vertebral column & trunk?

Answer 9

intrinsic

Question 10

the deep back muscles are made of 3 muscle groups, 2 of which are in extrinsic and the other is intrinsic. Name them.

Answer 10

extrinsic
- SUPERFICIAL vertical muscles
- Transverso-spinalis (INTERMEDIATE back muscles)
intrinsic — DEEPEST muscles of the vert column, AKA Segmental Muscles

Question 11

the extrinsic muscles of the thoracic wall, found in the upper and lower back

Answer 11

serratus posterior muscles (superior & inferior)

Question 12

muscles of the abdominal wall lack bony structures for protection, and instead have what?

Answer 12

LARGE MUSCLES to provide protection to produce gross movements

Question 13

how are the ab muscles involved in respiration?

Answer 13

due to ATTACHMENT of its muscles to the RIB CAGE

Question 14

unpaired bone which covers the back of the head

Answer 14

occipital bone

Question 15

pair of bilateral, symmetrical bones that make up a large part of the sides of the skull’s base

Answer 15

temporal bones

Question 16

in the anterior asp. of the abdominal wall, there’s 3 flat muscles and 2 vertically oriented muscles. Name them.

Answer 16

3 flat muscles = external & internal obliques, TVA (transversus abdominis)
2 vertically oriented muscles = RA, pyramidalis

Question 17

identify which of the ant muscles of the ab wall has the ff.

origin: lower 8 ribs (5-12)
insertion: linea alba, iliac crest, pubis

Answer 17

EO

Question 18

identify which of the ant muscles of the ab wall has the ff.

origin: ant surface of the pubis
insertion: linea alba

Answer 18

pyramidalis

Question 19

identify which of the ant muscles of the ab wall has the ff.

origin: lum fascia, iliac crest, lat of 2/3 inguinal lig
insertion: linea alba, pubis, lower 3 ribs

Answer 19

IO

Question 20

identify which of the ant muscles of the ab wall has the ff.

origin: lum fascia, iliac crest, lat of 1/3 inguinal lig
insertion: linea alba, pubis

Answer 20

TVA

Question 21

identify which of the ant muscles of the ab wall has the ff.

origin: symphysis pubis, pubic crest & tubercle
insertion: xiphoid proc, 5th-7th cc’s, pubis

Answer 21

RA

Question 22

T or F: the upper 6 cc’s and lat 2/3 of the inguinal lig is part of the TVA’s origin

Answer 22

F, it’s lower 6 cc’s & lat of 2/3 inguinal lig

Question 23

both the EO & IO are responsible for trunk flexion and rotation, but which does contralateral and ipsilateral rotation?

Answer 23

EO = contralateral rotation -> inf-med fiber orientation
IO = ipsilateral rotation -> sup-med fiber orientation

Question 24

action of pyramidalis

Answer 24

tenses the linea alba

Question 25

this ant ab muscle is AKA the “straight up muscle”, as it flexes the vert column, and is an antilordotic muscle as it promotes __ pelvic tilt

Answer 25

RA; post | post pelvic tilt = pelvis tilts post -> butt tilts ant => corrects posture

Question 26

which ant ab muscles act as ant flexors of the trunk?

Answer 26

bilateral action of EO & IO + RA

Question 27

the main function of this ant ab muscle is to provide stability

Answer 27

TVA

Question 28

the post asp. of the ab wall are made of 3 muscles, namely

Answer 28

psoas, quadratus lumborum, iliacus

Question 29

muscles of the post ab wall that - flexes the thigh on trunk, - if the thigh is fixed, flexes the trunk on the thigh (eg sitting up from lying down position)

Answer 29

psoas & iliacus, AKA iliopsoas muscle

Question 30

this post ab muscle - fixes & depresses the 12th rib (for inspiration & forced respiration resp) - ipsilateral flex of the vert column

Answer 30

quadratus lumborum

Question 31

the psoas & iliacus insert at what part of the femur?

Answer 31

lesser trochanter

Question 32

the quadratus lumborum insert at what rib?

Answer 32

rib 12

Question 33

the 2 superficial vertical muscles are made of 2 grps, namely?

Answer 33

cervical muscles; erector spinae

Question 34

the transversospinalis muscle group are made of 3 muscles, namely

Answer 34

semispinalis, multifidus, rotatores

Question 35

general action of the transversospinalis muscle group bilaterally & unilaterally are?

Answer 35

``` bilateral = trunk ext unilateral = contralateral trunk ext (via pulling SP to TP on opp side) ```

Question 36

collectively, this group of deep back muscles contribute to the stability of the vertebrae

Answer 36

deepest muscles of the vert column, AKA Segmental muscles

Question 37

the segmental muscles are made of 2 grps, namely?

Answer 37

interspinalis, intertransversarii

Question 38

T or F: due to the SHORT ATTACHMENT of the transverso-spinalis muscle grp, it mainly functions to STABILIZE the vert column during gross movement

Answer 38

T

Question 39

the transverso-spinalis muscle grp mainly originates & inserts at which parts of the vert?

Answer 39

origin: TP of vert => that’s why they’re called as transverso-spinalis insertion: SP of vert => insertions are medial to their origins

Question 40

this muscle grp of the superficial vertical muscles act as primary extensors of the vert column & head

Answer 40

erector spinae

Question 41

main movements of the erector spinae bilaterally & unilaterally

Answer 41

bi - back ext (straighten back) | uni - lat bend of vert column

Question 42

erector spinae is made of 3 muscles, namely

Answer 42

iliocostalis, longissimus, thoracis

Question 43

the cervical muscles are prime movers of which body parts?

Answer 43

head & neck

Question 44

name the 3 muscle grps of the cervical muscles

Answer 44

``` sternocleidomastoid (SCM) Spinotransverse grp (splenius capitis & cervicis) scalene muscles (ant, post, lat) ```

Question 45

cervical muscles that act as neck extensors

Answer 45

splenius capitis & cervicis, via bilatral contraction

Question 46

cervical muscles that cause head rotation

Answer 46

unilateral contraction of - SCM (contralateral) - splenius capitis & cervicis (ipsilateral)

Question 47

T or F: bilateral action of the SCM & Scalene cause neck flexion

Answer 47

T

Question 48

which cervical muscle does NOT cause head rotation? | choices: SCM, spinotransverse grp, scalene

Answer 48

Scalene - only does neck lat flex (ipsilateral), neck flex