Deep Back Muscles

Question 1

Erector Spinae

Answer 1

* Combination of 3 muscles: Iliocostalis, Longissimus and Spinalis

Common Origin: Iliac crest, sacral crest & lumbar spines

Question 2

Iliocostalis

Answer 2

(lateral)

I: Inferior ribs/ cervical transverse process

Inn: dorsal rami of spinal N.

BS: Posterior Intercostal A. & Lumbar A.

A: Ipsilateral bend & extend spine

Question 3

Longissimus

Answer 3

(intermediate)

I: thoracic/ cervical transverse process, mastoid process

Inn: dorsal rami of Spinal N.

BS: Posterior Intercostal A. & Lumbar A.

A: Ipsilateral bend & extend spine, extend head

Question 4

Spinalis

Answer 4

(medial)

I: thoracic/ cervical spines

Inn: dorsal rami on spinal N.

BS: posterior Intercostal A. & lumbar A.

A: extend spine & ipsilateral bend

Question 5

Transversospinalis

Answer 5

* Combination of 3 muscles

**upside down

Semispinalis Cervicis/ Capitus, Multifidus Lumborum & Rotatores Thoracis

Question 6

Semispinalis Cervicis/ Capitus

Answer 6

(4-6”)

O: C3 - T5 transverse processes

I: C2 - T4 vertebral spines, nuchal lines

Inn: dorsal rami of Spinal N.

BS: Posterior Intercostal A. & Vertebral A.

A. Extend head/ neck & ipsilateral bend

Question 7

Multifidus Lumborum

Answer 7

(2-4”)

O: L1 - S1 transverse processes

I: T12 - L5 vertebral spines

Inn: dorsal rami of Spinal N.

BS: Posterior Intercostal A. & Lumbar A.

A: stabilize vertebrae

Question 8

Rotatores Thoracis

Answer 8

(1-2”)

O: T1 - T12 transverse processes

I: C7 - T11 vertebral spines

Inn: dorsal rami of Spinal N.

BS: posterior Intercostal A.

A: assist rotation