Intrinsic Back Muscles

Question 1

Superficial intrinsic back muscles (1)

Answer 1

splenius

Question 2

Splenius - O

Answer 2

arises from nuchal ligament and spinous processes of C7-T6

Question 3

Splenius - N

Answer 3

posterior rami of spinal nerves

Question 4

Splenius - A

Answer 4

acting alone: lateral flexion of neck
rotation of head to ipsilateral side of muscle
acting together: extension of head and neck

Question 5

Intermediate intrinsic back muscles (3)

Answer 5

iliocostalis
longissimus
spinalis

Question 6

Erector spinae

Answer 6

iliocostalis
longissimus
spinalis

Question 7

Erector spinae- O

Answer 7

thoracolumbar fascia

Question 8

Erector spinae - N

Answer 8

posterior rami of spinal nerves

Question 9

Erector spinae - A

Answer 9

acting bilaterally: head and vertebral extension as back is flexed (controls movement by gradually lengthening fibers)
acting unilaterally: lateral flexion of vertebral column

Question 10

Deep intrinsic back muscles (3)

Answer 10

semispinalis (thoracis, cervicis, and capitis)
multifidus
rotatores (brevis and longus)

Question 11

Semispinalis - N

Answer 11

posterior rami of spinal nerves

Question 12

Semispinalis - A

Answer 12

extension and contralateral rotation of head, T-spine, and C-spine

Question 13

Multifidus - N

Answer 13

posterior rami of spinal nerves

Question 14

Multifidus - A

Answer 14

unilateral contraction rotates to contralateral side

vertebral stabilization during local movements of vertebral column

Question 15

Rotatores - N

Answer 15

posterior rami of spinal nerves

Question 16

Rotatores - A

Answer 16

proprioception
possible vertebral stabilization
assist local extension and rotation of vertebral column

Question 17

Minor deep intrinsic back muscles (3)

Answer 17

interspinales
intertransversaril
levatores costarum

Question 18

Interspinales - N

Answer 18

posterior rami of spinal nerves

Question 19

Interspinales - A

Answer 19

assist in vertebral extension and rotation

Question 20

Intertransversarii - N

Answer 20

anterior and posterior rami of spinal nerves

Question 21

Intertransversarii - A

Answer 21

assist in vertebral lateral flexion

bilaterally vertebral stabilization

Question 22

Levatores costarum - N

Answer 22

posterior rami of C8-T11 spinal nerves

Question 23

Levatores costarum - A

Answer 23

elevation of ribs
assist respiration
assist vertebral lateral flexion

Question 24

Transversospinales

Answer 24

semispinalis
multifidus
rotatores