5 Posterior Spinal Muscles

Question 1

Identify superficial muscles that overlie the intrinsic back muscles

Answer 1

trapezius, latissimus dorsi, levator scapulae and rhomboids (major and minor)

Question 2

View the thoracodorsal fascia and describe two functions of this strong structure

Answer 2

acts as an attachment site for the trapezius muscle, latissimus dorsi, gluteus maximus and the hamstrings group of muscle
this fascia has an important role in body movements (e.g. lifting).

Question 3

Describe the main functions provided by the erector spinae and the smaller deep intrinsic posterior spinal muscles

Answer 3

function
- Prime movers of extension
- Bilateral contraction
- Side flexion with unilateral contraction

Question 4

Superficial layer of intrinsic back muscles – S. S. L. I.

Answer 4

Splenius – cervical and thoracic region only

Spinalis - most medial column

Longissimus – intermediate column

Iliocostalis - most lateral column

Question 5

intermediate Layers of the Erector muscles MRS

Answer 5

a. Multifidus: postural, short
(largest in lumbar region)

Protects vertebral joints/ stabilize spine
b. Rotatores: postural, short, deepest
(most developed in thoracic region)
c. Semispinalis: thick, medial
(throughout the thoracic and cervical areas to cranium)

Question 6

deep layer of muscles

Answer 6

Connect transverse processes to transverse processes
a. Interspinales / interspinous
b. Intertransversales / intertransverse

Question 7

Muscles in the cervical Region

Answer 7

Suboccipital muscles – muscles specialized for movements of
extension, flexion and rotation; connections also to dura
Suboccipital triangle

Question 8

Origin insertion and action of the levator spinae

Answer 8

o= Transverse processes of vertebrae C1-C4
Insertion= Medial border of scapula
Action= Draws scapula superomedially, rotates glenoid cavity inferiorly, Lateral flexion of neck, extension of the neck

Question 9

Origin insertion and action of the rhomboid

Answer 9

major and minor
origin = Spinous processes
Insertion= Medial border of scapula
Action: Draws scapula superomedially, Rotates glenoid cavity inferiorly; Supports position of scapula

Question 9

Origin insertion and action of the rhomboid

Answer 9

major and minor
origin
Rhomboid minor: Spinous processes
Rhomboid major: Spinous process
Insertion
Rhomboid minor: medial end of spine of scapula
Rhomboid major: Medial border of scapula
Action: Draws scapula superomedially, Rotates glenoid cavity inferiorly; Supports position of scapula

Question 10

origin insertion and action of the spinalis

Answer 10

origin = spinous processes C7

Insertion= spinous process T8
Action = extension of head, cervical and thoracic spines
lateral flexion of cervical and thoracic spine

Question 11

origin insertion and action of longissimus

Answer 11

o = Transverse processes of vertebrae
insertion = Mastoid process of temporal bone
action = Extension of spine, Lateral flexion of spine

Question 12

origin insertion and action illicostalis

Answer 12

o = ribs
i = Angles of ribs 1-6, transverse process of vertebra C7
a = Extension of spine, Lateral flexion of spine

Question 13

origin insertion and action multifidus muscle

Answer 13

o = Superior articular processes of vertebrae
i = Lateral aspect and tips of the spinous processes of vertebrae
a = extension of spine, Lateral flexion of spine, rotation of spine

Question 14

origin insertion and action of rotators

Answer 14

o = Transverse processes
i = spinous process of vertebra
Actions= Extension of thoracic spine
Rotation of thoracic spine

Question 15

origin insertion action of semispinalis

Answer 15

o = Articular processes of vertebrae
Insertion= occipital bone
Action= extension of head, cervical and thoracic spine
lateral flexion of head, cervical and thoracic spine rotation of head, cervical and thoracic spine

Question 16

action of interspinous

Answer 16

Extension of cervical and lumbar spine

Question 17

action of inter-transverse

Answer 17

flex the spine