Muscles of the Spine/Neck

Question 1

What groups of back muscles are innervated by the dorsal rami of spinal nerves?

Answer 1

Intrinsic back musculature:

SUPERFICIAL

• splenius capitis
• splenius cervicis

INTERMEDIATE
-erector spinae: spinalis, longissimus, iliocostalis (LATERAL BRANCHES)

DEEP 
(TRANSVERSOSPINALES) 
-semispinalis (capitis, cervicis, thoracis) 
-multifidus
-rotatores (longus brevis)

• interspinaes
• intertransversarii

Question 2

What groups of back muscles are innervated by the ventral rami of spinal nerves?

Answer 2

EXTRINSIC BACK MUSCULATURE:

SUPERFICIAL: 
axio-appendicular: 
-trapezius (CN XI- EXCEPTION) 
-latissimus dorsi
-levator scapulae
-rhomboids

INTERMEDIATE:

• serratus posterior superior
• serratus posterior inferior
• —> intercostal nn. (ventral rami of spinal nn. at corresponding level)

Question 3

serratus posterior superior attachments

Answer 3

from spinous processes of C7-T3 to inferior borders of ribs 2-5

Question 4

serratus posterior superior function

Answer 4

proprioception of thoracic wall, accessory muscle in respiration

Question 5

serratus posterior superior innervation

Answer 5

intercostal nn. (T1-T4)

Question 6

serratus posterior inferior attachments

Answer 6

from spinous processes of T11-L2 to inferior borders of ribs 9-12

Question 7

serratus posterior inferior function

Answer 7

proprioception of thoracic wall, accessory respiration muscle

Question 8

serratus posterior inferior inn.

Answer 8

intercostal nn. (T9-12)

Question 9

Erector spinae attachments:

Answer 9

from TLF attached to the sacrum, iliac crest, spinous processes L5-T11, supraspinous lig., angles of ribs to costal angles (iliocostalis), ribs & transverse processes (longissimus), and spinous processes (spinalis)

SPINALIS: thoracis, cervicis, capitis (blends into semispinalis capitis)

LONGISSIMUS: capitis, cervicis, thoracis

ILIOCOSTALIS: cervicis, thoracis, lumborum

Question 10

erector spinae actions:

Answer 10

extension and lateral flexion of vertebral column

Question 11

semispinalis (transversospinales) attachments:

Answer 11

from transverse processes to distant superior spinous processes

3 MUSCLES of semispinalis:
-capitis, cervicis, thoracis

Question 12

semispinalis muscle actions:

Answer 12

extension & contralateral rotation of the vertebral column

Question 13

multifidus attachments

Answer 13

from sacrum, posterior SI ligament, posterior iliac spine, transverse processes to more superior spinous processes

**in between TPs and SPs

multifidus: sacral, lumbar, thoracic, cervical

Question 14

multifidus actions

Answer 14

extension & contralateral rotation of the vertebral column

Question 15

rotatores longus and brevis attachments:

Answer 15

transverse to spinous process of vertebra above (1-2 levels)

Question 16

rotatores longus and brevis actions:

Answer 16

extension & contralateral rotation of the vertebral column

Question 17

Interspinales attachments

Answer 17

between spinous processes of adjacent vertebrae

cervical (6), thoracic (2-3), lumbar (4)

Question 18

interspinales actions:

Answer 18

extension of spine, proprioception

Question 19

Intertransversarii attachments

Answer 19

between the transverse processes of adjacent vertebrae

Question 20

Intertransversarii action:

Answer 20

lateral flexion of the spine

Question 21

splenius cervicis attachments

Answer 21

from spinous processes of T3-T6 to posterior tubercles of transverse processes of C1-3

Question 22

splenius cervicis actions:

Answer 22

extension, lateral flexion, ipsilateral rotation

Question 23

splenius capitis attachments

Answer 23

from ligamentum nuchae and spinous processes T4-C7 to the mastoid process of the temporal bone

Question 24

splenius cervicis action:

Answer 24

extension, lateral flexion, ipsilateral rotation