Back Muscles

Question 1

what do extrinsic back muscles act on?

Answer 1

structures outside of back (appendicular skeleton)

Question 2

what do intrinsic back muscles act on?

Answer 2

structures within the back

Question 3

trapezius: origins and insertions

Answer 3

origins - nuchal ligament, spinous processes C7-T12

insertions - lateral clavicle (descending), acromiom (horizontal) and scapula spine (ascending)

Question 4

trapezius: actions and innervation

Answer 4

upper - scapula elevation, rotation, arm abduction
middle - scapula retraction
lower - inferiorly pull scapula

innervation - accessory nerve (CN11)

Question 5

latissimus dorsi: origins and insertion

Answer 5

origin - T6-12, thoracolumnar fascia, iliac crest, ribs 10-12

insertion - intertubular sulcus of humerus

Question 6

latissimus dorsi: actions and innervation

Answer 6

arm - adduction, medial rotation, extension
shoulder girdle - depression, pulls scapula medially

innervation - thoracodorsal nerve

Question 7

levator scapulae: origin and insertion

Answer 7

origin - transverse processes C1-4

insertion - medial scapula border

Question 8

levator scapulae: action and innervation

Answer 8

action - scapula elevation

innervation - dorsal scapular nerve

Question 9

rhomboid minor: origin and insertion

Answer 9

origin - spinous processes C7-T1

insert - medial scapula border (at spine level)

Question 10

rhomboid minor: actions and innervation

Answer 10

actions - retracts/rotates scapula

innervation - dorsal scapular nerve

Question 11

rhomboid major: origin and insertion

Answer 11

origin - spinous processes T2-5

insert - medial scapula border (between spine and inferior angle)

Question 12

rhomboid major: actions and innervation

Answer 12

actions - retracts/rotates scapula

innervation - dorsal scapular nerve

Question 13

what is the general function of intrinsic back muscles?

Answer 13

maintain posture and control vertebral movement

Question 14

where does the thoracolumnar fascia cover and attach to?

Answer 14

covers deep back muscles

attaches to lat dorsi and trapezius

Question 15

what is the function of the thoracolumnar fascia?

Answer 15

organisation and integrity of the region (deep back muscles)

Question 16

splenius capitis: origins and insertions

Answer 16

origins - lower nuchal ligament, C7/T3-4

insertions - mastoid process and occipital bone of skull

Question 17

splenius capitis: action and innervation

Answer 17

action - rotates head same side

innervation - spinal nerves 3/4 (posterior rami)

Question 18

splenius cervicis: origin and insertion

Answer 18

origin - spinous processes T3-6

insert - transverse processes C1-4

Question 19

splenius cervicis: action and innervation

Answer 19

action - rotates head same side

innervation - lowest cervical spinal nerves (posterior rami)

Question 20

iliocostalis: origin and insertions

Answer 20

origin - common tendinous origin

insertions - costal angle of ribs, cervical transverse processes

Question 21

iliocostalis: actions and innervation

Answer 21

actions - flex vertebral column (unilateral), extend vertebral column/head (bilateral)

innervation - spinal nerves (posterior rami)

Question 22

longissimus: origin and insertions

Answer 22

origin - common tendinous origin

insertions: lower ribs, transverse processes C2-T12, mastoid process of skull

Question 23

longissimus: actions and innervation

Answer 23

actions - flex vertebral column (unilateral/lateral), extend vertebral column (bilateral)

innervation - spinal nerves (posterior rami)

Question 24

spinalis: origin and insertions

Answer 24

origin - common tendinous origin

insertions - spinous processes C2 and T1-8, occipital bone of skull

Question 25

spinalis: actions and innervation

Answer 25

actions - flex vertebral column (unilateral/lateral), extend vertebral column (bilateral)

innervation - spinal nerves (posterior rami)

Question 26

semispinalis: origin and insertions

Answer 26

origin - transverse processes C4-T10

insert - spinous processes C2-T4, occipital bone (skull)

Question 27

semispinalis: actions and innervation

Answer 27

actions - extends/controlaterally rotates head/vertebral column

innervation - spinal nerves (posterior rami)

Question 28

which intrinsic back muscles are superficial/intermediate and deep

Answer 28

splenius capitis (S)
splenius cervicis (S)
iliocostalis (I)
longissimus (I)
spinalis (I)
semispinalis (D)
multifundus (D)

Question 29

name the 3 additional back muscles

Answer 29

levatores costarum
interspinales
intertransversarii