Intrinsic muscles of the back

Question 1

Iliocostalis lumborum

Answer 1

O: Sacrum, Iliac crest, thoracolumbar fascia
I: 6th-12th ribs, deep layer of fascia
A:
Bilateral: spine extension
Unilateral: ipsilateral lateroflexion
In: Posterior branches of spinal nn.

Question 2

Iliocostalis thoracis

Answer 2

O: 7th-12th ribs
I: 1st-6th rib
A:
Bilateral: spine extension
Unilateral: ipsilateral latero flexion
In: Posterior branches of spinal nn.

Question 3

Iliocostalis cervicis

Answer 3

O: 3rd-7th ribs
I: Transverse processes of C4-C6
A:
Bilateral: spine extension
Unilateral: ipsilateral latero flexion
In: Posterior branches of spinal nn.

Question 4

Longissimus thoracis

Answer 4

O: Os sacrum, Iliac crest, SP of L1-L5, TP of T7-T12
I: 2nd-12th ribs, Costalis processes L1- L5, Transverse processes T1-T12
A:
Bilateral: spine extension
Unilateral: ipsilateral latero flexion
In: Posterior branches of spinal nn.

Question 5

Longissimus cervicis

Answer 5

O: TP of T1-T6
I: TP of C2-C5
A:
Bilateral: spine extension
Unilateral: ipsilateral spine latero flexion
In: Posterior branches of spinal nn.

Question 6

Longissimus capitis

Answer 6

O: TP of T1-T3, Transverse and articular processes C4- C7
I: Mastoid process
A:
Bilateral: extension of the head
Unilateral: ipsilateral flexion, rotation of the head
In: Posterior branches of spinal nn.

Question 7

Splenius cervicis

Answer 7

O: SP T3-T6
I: TP C1-C2
A:
Bilateral: extension of the cervical spine and head
Unilateral: ipsilateral flexion and rotation of the head
In: Posterior branches of spinal nn.

Question 8

Splenius capitis

Answer 8

O: SP C3-T3
I: Mastoid process, Superior nuchal line
A:
Bilateral: extension of the cervical spine and head
Unilateral: ipsilateral flexion and rotation of the head
In: Posterior branches of spinal nn.

Question 9

Spinalis cervicis

Answer 9

O: SP C5-T2
I: SP C2-C5
A:
Bilateral: extension of the cervical spine
Unilateral: ipsilateral latero flexion of the cervical spine
In: Posterior branches of spinal nn.

Question 10

Spinalis thoracic

Answer 10

O: SP of T10-L3
I: SP of T2- T8 (2)
A:
Bilateral: extension of the thoracic spine
Unilateral: ipsilateral latero flexion of the thoracic spine
In: Posterior branches of spinal nn.

Question 11

Rotator breves (1) and longi (2)

Answer 11

O and I:
From TP T1-T12 to SP of the next higher vertebrae (1) or two levels higher (2)
A:
Bilateral: extension of thoracic spine
Unilateral: controlateral rotation of the thoracic spine
In: Posterior branches of spinal nn.

Question 12

Multifidus

Answer 12

O: Sacrum, ilium, mamillary process of L1-L5, transverses and articular processes of C4-C7 and T1-T4
I: SP two to four levels higher
A:
Bilateral: extension of the spine
Unilateral: ipsilateral latero flexion and contro lateral rotation of the spine
In: Posterior branches of spinal nn.

Question 13

Semispinalis thoracis

Answer 13

O: TP T6-T12
I: SP of C6-T4
A:
Bilateral: extension of the thoracic spine
Unilateral: ipsilateral lateroflexion and controlateral rotation of the thoracic spine
In: Posterior branches of spinal nn.

Question 14

Semispinalis cervicis

Answer 14

O: TP of T1-T6
I: SP of C2-C5
A:
Bilateral: extension of the cervical spine
Unilateral: ipsilateral lateroflexion and controlateral rotation of the cervical spine
In: Posterior branches of spinal nn.

Question 15

Semispinalis capitis

Answer 15

O: TP of C3-T6
I: Occipital bone between sup and inf nuchal line
A:
Bilateral: extension of the head
Unilateral: ipsilateral lateroflexion and controlateral rotation of the head
In: Posterior branches of spinal nn.

Question 16

Serratus posterior superior

Answer 16

Form: Quadrangular
O: Nuchal ligament, SP of C7-T3
I: Superior border of 2th-5th rib
A: Lift ribs -> active in inspiration
In: Intercostales n.

Question 17

Serratus posterior inferior

Answer 17

O: SP T11-L2 and thoracolumbar fascia
I: Inferior border of 9th-11th ribs
A: Lowers ribs -> active in expiration
Prevents narrowing the thoracic
aperture
In: Anterior branches of spinal nn.