Spinal muscles

Question 1

Why are the superficial and intermediate back muscles defined as extrinsic muscles?

Answer 1

They don’t develop embryologically in the back

Question 2

Why are the deep back muscles defined as intrinsic muscles?

Answer 2

They develop embryologically in the back

Question 3

Generally, where do all of the superficial back muscles originate and attach to, and why?

Answer 3

Originate from vertebral column

Attach to shoulder bones

Because they are associated with movements of upper limb

Question 4

Where is trapezius, and what are its sites of origin and attachment?

Answer 4

1

Originates from skull, nuchal ligament (ligament at back of neck that is continuous with supraspinous ligament), spinous processes C7-T12

Attaches to clavicle, acromion process, scapula spine

Question 5

What nerve innervates trapezius, and what are its 3 motor actions?

Answer 5

Innervated by accessory nerve

Upper fibres: Elevate and rotate scapula during arm abduction

Middle fibres: Retract scapula

Lower fibres: Pull inferiorly/depress scapula

Question 5

What is the nuchal ligament, and which superficial back muscle originates from here?

Answer 5

ligament at back of neck that is continuous with supraspinous ligament

Origin site of trapezius

Question 6

Where is latissimus dorsi, and what are its sites of origin and attachment?

Answer 6

5

Originates from iliac crest, spinous processes T6-T12, thoracolumbar fascia

Attaches to bicipital groove/intertubercular sulcus of humerus

Question 7

Which nerve innervates latissimus dorsi, and what are its 3 motor actions?

Answer 7

Thoracodorsal nerve

Upper arm extension, adduction, medial rotation

Question 8

Where is levator scapulae, and what are its origin and attachment sites?

Answer 8

11

Originates from transverse processes of C1-C4

Attaches to scapula medial border

Question 9

Which nerve innervates levator scapulae, and what is its motor action?

Answer 9

Innervated by dorsal scapular nerve

Elevates scapula

Question 10

Is rhomboid minor or major more superficial?

Answer 10

Rhomboid minor is superficial to rhomboid major

Question 11

Where is rhomboid minor, and what are its origin and attachment sites?

Answer 11

10

Originates from spinous processes C7-T11

Attaches to scapula medial border at level of scapula spine

Question 12

Which nerve innervates rhomboid minor, and what are its 2 motor actions?

Answer 12

Dorsal scapular nerve

Retracts/pulls inferiorly scapula

Rotates scapula

Question 13

Where is rhomboid major, and what are its origin and attachment sites?

Answer 13

7

Originates from spinous processes T2-T5

Attaches to medial border of scapula

Question 14

Which nerve innervates rhomboid major, and what are its 2 motor actions?

Answer 14

Dorsal scapular nerve

Rotates scapula

Retracts/pulls inferiorly scapula

Question 15

What are the 2 intermediate back muscles, and what nerve innervates them and what is their motor action?

Answer 15

Serratus posterior superior: Elevates ribs 2-5

Serratus posterior inferior:
Depresses ribs 9-12

Innervated by intercostal nerve

Question 16

Where is serratus posterior superior, and what are its origin and attachment sites?

Answer 16

8

Originates from lower part of nuchal ligament and cervical spine

Attaches to ribs 2-5

Question 17

Which 2 muscles is serratus posterior superior directly deep to?

Answer 17

Rhomboid major and minor

Question 18

Where is serratus posterior inferior, and what are its origin and attachment sites?

Answer 18

15

Originates from thoracic and lumbar spine

Attaches to ribs 9-12

Question 19

Which muscle is serratus posterior inferior directly deep to, and directly inferior to?

Answer 19

Directly deep to latissimus dorsi

Directly inferior to serratus anterior

Question 20

How does the direction of muscles fibres in serratus posterior superior and inferior determine what direction they pull the ribs in?

Answer 20

Serratus posterior superior: Fibres run inferolateral, so when they contract they will pull ribs up

Serratus posterior inferior: Fibres run superolateral, so when they contract they will pull ribs down

Question 21

In the deep back, what are the 2 spinotransversales, and what is the function of these muscles?

Answer 21

Splenius capitis

Splenius cervicis

Movements of head and neck

Question 22

Which group of deep back muscles control movements of head and neck?

Answer 22

Spinotransversales:

Splenius capitis

Splenius cervicis

Question 23

Where is splenius capitis, and what are its origin and attachment sites?

Answer 23

13

Originates from lower aspect of nuchal ligament and spinous processes C7-T4

Attaches to mastoid process and occipital bone of skull

Question 24

Which 2 posterior rami innervate splenius capitis?

Answer 24

C3 and C4

Question 25

Where is splenius cervicis, and what are its origin and attachment sites?

Answer 25

12 Originates from spinous processes T3-T6 Attaches to transverse processes C1-C3

Question 26

Which posterior rami innervate splenius cervicis?

Answer 26

Posterior rami of lower cervical nerves

Question 27

Which 3 deep back muscles form a column called the erector spinae, and where is the erector spinae, and why are they all included in this group?

Answer 27

10 Iliocostalis Longissimus Spinalis They all originate from common tendon origin

Question 28

Where is iliocostalis cervicis, and what part of iliocostalis does it arise from, and what are the attachment sites?

Answer 28

4 Arises from costal angles (angle where rib changes direction to form cage shape) of ribs 3-6 Attaches to transverse processes C4-C6

Question 29

What are the 2 main motor actions of iliocostalis cervicis?

Answer 29

Lateral flexion (unilateral action of one side of spine only) and extension of lower cervical spine (bilateral)

Question 30

Where is iliocostalis thoracis, and what part of iliocostalis does it arise from, and what are the attachment sites?

Answer 30

6 Arises from costal angles of ribs 7-12 Attaches to angles of ribs 1-6 and C7 transverse process

Question 31

What are the 2 motor actions of iliocostalis thoracis?

Answer 31

Lateral flexion (unilateral) and extension (bilateral) of thoracic spine

Question 32

Where is iliocostalis lumborum, where does it arise from in the iliocostalis and where does it attach?

Answer 32

Arises from common erector spinae tendon Attaches to angles of ribs 7-12

Question 33

What are the 2 motor actions of iliocostalis lumborum?

Answer 33

Lateral extension and flexion of lumbar spine

Question 34

List the erector spinae muscles from most lateral to most medial?

Answer 34

Iliocostalis, longissimus, spinalis

Question 35

Where is longissimus capitis, where does it arise from and where does it attach?

Answer 35

1 Arises from transverse processes T1-T5 Attaches to transverse processes C4-C7, then inserts onto lateral surface of mastoid process of temporal bone

Question 36

What are the 2 main actions of longissimus capitis?

Answer 36

Bilateral contraction: Head and neck extension Unilateral contraction: Ipsilateral head and neck lateral flexion and rotation

Question 37

Where is longissimus cervicis, where does it arise from and where does it attach?

Answer 37

5 Arises from transverse processes T1-T5 Attaches to transverse processes C2-C6

Question 38

Where is longissimus thoracis?

Answer 38

7

Question 39

What are the overall 2 functions of longissimus muscles acting together?

Answer 39

Spine extension Ipsilateral spine lateral flexion

Question 40

Where is spinalis, and what are the 3 divisions?

Answer 40

Spinalis capitis: 2 Spinalis cervicis: 3 Spinalis thoracis: 9

Question 41

What are the 2 main actions of spinalis?

Answer 41

Bilateral contraction: Extension of head, cervical spine, thoracic spine Unilateral contraction: Ipsilateral lateral flexion of head, cervical spine, thoracic spine