Back Muscles - Intrinsic

Question 1

Splenius Cervicis/Capitis
[Superficial Layer]
Origin (Proximal)

Insertion (Distal)

Action

Answer 1

Origin:

• Nuchal lig.
• SP of C7-T6

Insertion:
[Capitis] - mastoid process; lateral 3rd of sup. nuchal line
[Cervicis] - tubercles of TP of C1-C3/C4

Action:
[Alone] - side-bending/rotation of head
[Combined] - neck/head extension

Question 2

Erector Spinae {3 groups}
[Intermediate Layer]
Origin (Proximal)

Insertion (Distal)

Action

Answer 2

Origin [All]:

• Posterior iliac crest
• Posterior sacrum
• SI ligaments
• Sacral/inferior lumbar SPs
• Supraspinous ligament

Insertion:
[Iliocostalis] - angles of lower ribs & cervical TP
[Longissimus] - ribs (between tubercles & angles) to TP in thoracic/cervical regions and to mastoid process
[Spinalis] - SP in upper thoracic region & cranium

Action:
[Unilaterally] - side-bending
[Bilaterally] - trunk/head extension; controlled movement of back during trunk flexion (eccentrically)

Question 3

Transversospinalis - Semispinalis
{3 parts?}
[Deep Layer]
Origin (Proximal)

Insertion (Distal)

Action

Answer 3

{3 parts}: thoracis, cervicis, capitis

Origin:
-TP of C4-T12

Insertion:

• Fibers run superomedially to occipital bone & SP in thoracic/cervical regions
• Spans 4-6 segments

Action:

• Head & thoracic/cervical vertebrae column extension
• Contralateral rotation of head & upper vertebrae

Question 4

Transversospinalis - Multifidus
[Deep Layer]
Origin (Proximal)

Insertion (Distal)

Action

Answer 4

Origin:

• SI ligaments
• TP of T1-T3
• Articular processes C4-C7
• Mammillary process of lumbar vertebrae
• Posterior sacrum
• PSIS
• Aponeurosis of ES

Insertion:

• Fibers run obliquely/superomedially to entire length of SP
• Spans 2-4 segments

Action:
-Stabilize vertebrae during local movements of VC

Question 5

Transversospinales - Rotatores (brevis & longus)
[Deep Layer]
Origin (Proximal)

Insertion (Distal)

Action

Answer 5

Origin:
-TP of vertebrae

Insertion:

• FIbers run superomedially to attach to lamina/TP junction or SPs
• Span 1 (brevis) or 2 (longus) vertebrae superior to origin

Action:

• Stabilize vertebrae
• Assist with local extension/rotatory movements of VC
• Proprioception

Question 6

Interspinales
[Minor Deep Layer]
Origin (Proximal)

Insertion (Distal)

Action

Answer 6

Origin:
-Superior surfaces of cervical/lumbar SPs

Insertion:
-Inferior surfaces of SPs superior to origin

Action:
-Assist with trunk extension/rotation

Question 7

Intertransversarii
[Minor Deep Layer]
Origin (Proximal)

Insertion (Distal)

Action

Answer 7

Origin:
-TPs of cervical/lumbar spine

Insertion:
-TPs of adjacent vertebrae

Action:

• Assist trunk side-bending
• Stabilizes VC acting bilaterally

Question 8

Levatores Costarum
[Minor Deep Layer]
Origin (Proximal)

Insertion (Distal)

Action

Answer 8

Origin:
-TP tips of C7-T11

Insertion:
-Fibers run inferolaterally to ribs between tubercles & angles

Action:

• Elevate ribs
• Assist with respiration
• Assist trunk side-bending

Question 9

3 Groups of Iliocostalis (in order)

Answer 9

(1) Lumborum
(2) Thoracis
(3) Cervicis

Question 10

3 Groups of Longissimus (in order)

Answer 10

(1) Thoracis
(2) Cervicis
(3) Capitis

Question 11

3 Groups of Spinalis (in order)

Answer 11

(1) Thoracis
(2) Cervicis
(3) Capitis

Question 12

Deep Fascia

What does it do?
Where does it attach?

Answer 12

Purpose: encloses intrinsic back muscles

Attaches:

• Medially: nuchal lig.; SPs; supraspinous ligs., median sacral crest
• Laterally: cervical/thoracic TPs; rib angles

Question 13

Thoracolumbar Fascia

____ in ______ region.
____ and _______ in ________ region.

Answer 13

• Thin; thoracic

- Thick; strong; lumbar