Wk 5: Intrinsic Back Muscles

Question 1

Splenius Capitis (Spinotransverales)

Answer 1

O: Ligamentum nuchae & spinous processes of C7-T3 (sometimes T5/T5)
I: Mastoid Process and superior nuchal line
N: Posterior rami of middle cervical nerves
A: Bilaterally extend neck, unilateral rotate head

Question 2

Splenius Cervicis (Spinotransversales)

Answer 2

O: Spinous processes of T3-T6
I: Transverse processes of C1-C3
I: Posterior rami lower cervical nerves
A: Bilaterally extend neck, unilaterally rotate head

Question 3

Iliocostalis (Erector Spinae)

Answer 3

-most lateral
-associated with costal elements
-passes from common tendon of origin to multiple insertions into angles of ribs

Question 4

Longissimus (Erector Spinae)

Answer 4

-intermediate
-largest column
-extends from tendon of origin to skull

Question 5

Spinalis (Erector Spinae)

Answer 5

-medial
-most constant in thoracic region
-generally absent in cervical region

Question 6

Erector Spinae muscles function

Answer 6

Primary extensors of vertebral column.
Bilateral contraction straightens back and returns to upright position from flexed position.
Unilateral contraction bends the vertebral column laterally.

Question 7

Semispinalis (Tranversospinales)

Answer 7

-most superficial among transverospinales muscles
-begin in lower thoracic region & end in occipital bone
-span bw 4-6 vertebrae

Question 8

Multifidus (Transversospinales)

Answer 8

-deep to semispinalis
-span length of vertebral column
-from transverse processes to spinous processes
-span between 2-4 vertebrae

Question 9

Rotatores (Transversospinales)

Answer 9

-smallest and deepest among transversospinales muscles
-span the length of the vertebral column but best developed in the thoracic region
-fibers pass upward and medially from transverse processes to spinous processes
-Long rotators= cross 2 vertebrae
-Short rotators=attach to adjacent vertebrae

Question 10

Transversospinales Muscles Function

Answer 10

Bilateral contraction extends vertebral column, similar to erector spinae group
Unilateral contraction pulls spinous processes toward transverse processes to rotate the trunk.

Question 11

Semispinalis Capitis (Transversospinales)

Answer 11

O: T1-T6 transverse processes
I: Inferior nuchal area

Question 12

Semispinalis Thoracis (Transversospinales)

Answer 12

O: T6-T10 transverse processes
I: Spinous processes of upper 4 TV and lower CV

Question 13

Multifidus (Transversospinales)

Answer 13

O: Sacrum, PSIS, mammillary processes of LV, transverse processes of TV, articular processes of lower CV
I: Spinous processes (L5-C2)

Question 14

Rotatores Thoracis (Transversospinales)

Answer 14

O: Mammillary processes of LV, Transverse processes of TV, and articular processes of CV
I: Spinous processes

Question 15

Segmental Muscles 1st group

Answer 15

Levator Costarum
A: elevates the ribs
I: posterior rami of spinal nerves

Question 16

Segmental Muscles 2nd group

Answer 16

Interspinales & Intertransversarii
A: stabilize vertebrae during movements of vertebral column
I: posterior rami of spinal nerves

Question 17

Serratus Posterior Superior

Answer 17

O: Ligamentum nuchae, spinous processes of C7-T2 & supraspinous ligaments
I: Upper border of ribs 2-5
A: Elevation of ribs 2-5
I: Intercostal nerves (T1-T5)

Question 18

Serratus Posterior Inferior

Answer 18

O: Spinous processes of T11-L3 & supraspinous ligaments
I: Lower borders of ribs 9-12
A: Depresses ribs 9-12
I: Intercostal nerves (T9-T12)