vertebral column muscles

Question 1

Generally,

Answer 1

Smaller, deeper muscles = close to the joint & cross fewer joints … fine tuning of movements
= rich in muscle spindles
… proprioceptive role and segmental control
* Larger, superficial muscles = greater PCSA,
greater moment arms (leverage)
… produce movements

Question 2

AXIO-APPENDICULAR MUSCLES: trapezius

Answer 2

Bilateral contraction:
Cervical extension
Unilateral contraction:
ipsilateral lateral flexion contralateral axial rotation

Question 3

AXIO-APPENDICULAR MUSCLES: levator scapulae

Answer 3

Bilateral contraction:
Cervical extension
Unilateral contraction:
ipsilateral LF
ipsilateral axial rotation (if scapula fixed)

Question 4

AXIO-APPENDICULAR MUSCLES: sternocleidomastoid

Answer 4

Bilateral contraction:
Upper cervical extension
Lower cervical flexion*
Unilateral contraction:
Ipsilateral lateral flexion Contralateral axial rotation
R rotation = L SCM + R splenius

Question 5

AXIAL MUSCLES

Answer 5

1. anterior
2. lateral
3. posterior
   I. sub-occipital
   II. segmental
   III. transversospinales
   IV. erector spinae
   V. spinotransverse

Question 6

axial MUSCLES – CERVICAL anterior

Answer 6

1 Rectus capitis anterior
2 Rectus capitis lateralis
3 longus capitis flex head & upper Csp C1
4 longus colli (cervicis) cervical flexion
* Innervated by ventral rami cervical nerves

Question 7

axial MUSCLES – CERVICAL lateral

Answer 7

1 Anterior scalene
2 Middle scalene
3 Posterior scalene
* Innervated by ventral rami cervical nerves

Question 8

Posterior: intrinsic muscles of the back: Suboccipital group

Answer 8

Suboccipital group
1 Rectus capitis posterior minor 2 Rectus capitis posterior major 3 Obliquus capitis superior
4 Obliquus capitis inferior

Question 9

Posterior: intrinsic muscles of the back:Segmental muscles

Answer 9

Segmental muscles
1 Interspinales
2 Intertransversales – medial only NOT lateral

Question 10

Posterior: intrinsic muscles of the back:

Transversospinales

Answer 10

Transversospinales
1 Rotatores
2 Multifidus
3 Semispinalis

Question 11

Posterior: intrinsic muscles of the back:Erector spinae

Answer 11

Erector spinae
1 Spinalis
2 Longissimus 3 Iliocostalis

Question 12

Posterior: intrinsic muscles of the back: Spinotransverse

Answer 12

Spinotransverse

1 Splenius

Question 13

suboccipital group

Answer 13

Innervation: suboccipital nerve = dorsal ramus of C1
•Rectus capitis posterior minor (C1 – occiput)
•Rectus capitis posterior major (C2 sp p - occiput) •Obliquus capitis superior (C1 tp – occiput)
•Obliquus capitis inferior** (C2 sp p – C1 tp)
Combined action:
Bilateral = head /C1 extension on C2 Unilateral = ipsilateral axial rotation / LF

Question 14

Segmental muscles

Answer 14

interspinales (Cx / Lx) / medial intertransversarii (Cx)
Small PCSA
Small moment arms
= small force production Proprioceptive function?
“all unisegmental muscles of the vertebral column have between 2 to 6 times the density of muscle spindles found in the longer polysegmental muscles”
NB: intertransversarii (lateral) are not intrinsic back muscles – they are innervated by ventral rami

Question 15

transversospinales

Answer 15

attach to inferior transverse processes & superior spinous processes
Rotatores:
brevis & longus
most developed in Tx region but still very small PCSA = proprioceptive?
Multifidus:
:more oblique alignment in Tx … better line of action for segmental rotation & lateral flexion than in lumbar region
most developed in lumbar spine
Semispinalis
most developed in cervical & capitis regions
= main cervical extensors
(semispinalis thoracis spinous attachment C7 – T4)

Question 16

AXIAL MUSCLES posterior - transversospinales

Answer 16

•run from transverse processes in a superomedial direction to the spinous processes of superior vertebrae
DEEP TO SUPERFICIAL:
•rotatores not well developed in the Cx •multifidus
•semispinalis capitis •semispinalis cervicis
Prime movers of cervical extension

Question 17

AXIAL MUSCLES posterior - erector spinae

Answer 17

•Iliocostalis cervicis
•longissimus cervicis
•spinalis cervicis / capitis blend with
semispinalis cervicis / capitis

Question 18

AXIAL MUSCLES posterior – spinotransverse:

Answer 18

• splenius capitis
• splenius cervicis
bilateral: head & neck extension unilateral: ipsilateral axial rotation / LF