Intrinsic Back Muscles

Question 0

What muscles make up the intermediate layer of the intrinsic back muscles? What is this group called?

Answer 0

Erector spinal group

Iliocostalis, longissumus and spinalis

Question 1

What is the superficial layer of the intrinsic back muscles ?

Answer 1

Splenius

Question 2

What muscles make up the deep layer of the intrinsic back and what is this group called?

Answer 2

Transversospinalis.

Semispinalis, multifidus, rotatores (brevis and longus).

Question 3

What muscles make up the minor deep layer of the intrinsic back muscles ?

Answer 3

Interspinales, intertransverii, and levatores costarum.

Question 4

Proximal and distal attachment of the splenius

Answer 4

P: Nuchal ligament and spinous processes of C7-T6 (including capitis and cervicis)
D: splenius capitis- fibers run to the mastoid process and Nuchal line
splenius cervicis- tubercles of transverse processes of C1-C3 or C4 vertebrae.

Question 5

Nerve supply for splenius

Answer 5

Posterior rami of spinal nerves

Question 6

Action of splenius

Acting alone and together

Answer 6

Alone : laterally flex head and rotate head to side of active muscle (ipsilateral).
Together: extend head and neck

Question 7

Origin of erector spinae muscles ( iliocostalis, longissimus, spinalis)

Answer 7

Arise from iliac crest tendon, posterior part of sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes and supraspinous ligament

Question 8

Distal attachment of iliocostalis

Answer 8

Lumborum thoracis cervicis - fibers run to angles of lower ribs and cervical transverse processes

Question 9

Distal attachment of longissimus

Answer 9

Thoracis cervicis capitis- fibers run to ribs between tubercles and angles to transverse processes in thoracic and Cervicle regions and to mastoid process

Question 10

Distal attachment of spinalis

Answer 10

Thoracis, cervicis, capitis, fibers run to spinous processes in upper thoracic region and to cranium

Question 11

Nerve supply to erector spinae muscles

Answer 11

Posterior rami of spinal nerves

Question 12

Main actions of erector spinae acting alone and unilaterally

Answer 12

Bilaterally: extend VC and head. Control movement via eccentric contraction
Unilaterally: laterally flex VC

Question 13

Origin and insertion if the Semispinalis (part of Transversospinalis-deep later)

Answer 13

O: rises from transverse processes of C4-T12
I: thoracis cervicis capitis- fibers run superomedially to occipital bone and spinous processes in thoracic and spinal regions

Question 14

Innervation of the Transversospinalis muscles (deep layer- Semispinalis, multifidus, rotatores)

Answer 14

Posterior rami of spinal nerves (Semispinalis by Cervicle and upper thoracic posterior rami)

Question 15

Action of Semispinalis

Answer 15

Extension- head and thoracic and cervical region of vertebral column and rotates head controlaterally

Question 16

Action of multifidus (Transversospinalis) - deep

Answer 16

Stabilises vertebrae during local movement of VC

Question 17

Origin and insertion of the multifidus

Answer 17

O: arises from sacrum and transverse processes of c2-l5
I: fibers pass obliquely superiomedially to entire length of spinous processes superior to their origins.

Question 18

Main action of the rotatores (brevis and longus) part of Transversospinalis deep layer

Answer 18

Stabilise vertebrae and assist in local extension and rotational movements of VC - proprioception as we’ll

Question 19

Origin and insertion rope rotatores (brevis and longus)

Answer 19

O: arise from transverse processes of vertebrae
I: superiomedially to lamina of vertebrae above or spinous processes immediately above (brevis) or 2 segments up (longus)

Question 20

Muscles of the minor deep layer

Answer 20

Interspinales
Intertransverii
Levatores costarum.

Question 21

Origin and insertion of Interspinales

Answer 21

O: superior surfaces of spinous processes of cervical and lumbar vertebrae.
I: inferior surfaces of spinous processes of vertebrae superior

Question 22

Innervation of Interspinales

Answer 22

Posterior rami of spinal nerves

Question 23

Main action of Interspinales

Answer 23

Air in extension and rotation of VC

Question 24

Origin and insertion of intertransverii

Answer 24

O: transverse process of cervical and lumbar vertebrae
I: transverse process of adjacent vertebrae

Question 25

Innervation of intertransverii

Answer 25

Posterior and anterior rami of spinal nerves

Question 26

Action of intertransversii

Answer 26

Aid in lateral flex ion of vertebral column

Bilaterally- stabilise VC

Question 27

Origin and insertion of levatores costarum

Answer 27

O: tips of transverse processes of C7 and T1-T11.
I: inferno laterally insert on rib between tubercle and angle of ribs 1-12

Question 28

Innervation of levator costarum

Answer 28

Posterior rami of C8- T11 spinal nerves

Question 29

Action of levator costarum

Answer 29

Elevate ribs assisting in respiration, assists with lateral flexion of VC