Intrinsic Back Muscles.txt

• Nuchal Ligament
• spinous processes of C7 - T3/T4

• Mastoid process
• Lateral 1/3 superior nuchal line

Posterior rami of spinal nerves (C4 - C8)

• Branches of Occipital A.
• Transverse Cervical A. (superficial branches)

Alone: Lateral flex neck and rotate head to side.

Together: Extend head and neck

• Nuchal Ligament
• Spinous processes of T3 - T6

Transverse processes C1 - C3/C4

Posterior rami of spinal nerves (C4 - C8)

• Branches of Occipital A.
• Transverse Cervical A. (superficial branches)

Alone: Lateral flex neck and rotate head to side.

Together: Extend head and neck

Sacrum, Illiac crest, Spinous process of T11 - L5

• LUMBORUM / THORACIS / CERVICIS
• Fibers run superiorly to angles of lower ribs and cervicle transverse processes

Posterior rami of spinal nerves (segmental)

Bilaterally: Extend vertebral column and head; as back is flexed, control movement as their fibers are lengthened (eccentric contraction)

Unilaterally: Laterally flex vertebral column

Sacrum, Illiac crest, Spinous process of T11 - L5

• THORACIS / CERVICIS / CAPITIS
• Fibers run superiorly to ribs between tubercles and angles to transverse processes in thoracis and cervical regions, and to mastoid process

Posterior rami of spinal nerves (segmental)

Bilaterally: Extend vertebral column and head; as back is flexed, control movement as their fibers are lengthened (eccentric contraction)

Unilaterally: Laterally flex vertebral column

Sacrum, Illiac crest, Spinous process of T11 - L5

• THORACIS / CERVICIS / CAPITIS
• Fibers run superiorly to spinous processes in the upper thoracic regions and to cranium

Posterior rami of spinal nerves (segmental)

Bilaterally: Extend vertebral column and head; as back is flexed, control movement as their fibers are lengthened (eccentric contraction)

Unilaterally: Laterally flex vertebral column

Transverse processes of C4 - T12

• THORACIS / CERVICIS / CAPITIS
• Occipital bone and spinous processes in thoracis and cervical regions
• (spanning 4-6 segments)

Posterior rami of spinal nerves (segmental)

Extends head and thoracic and cervical regions of vertebral column

Rotates spine and head contralaterally

Sacrum, illium, aponeurosis of erector spinae, transverse processes of all vertebra except C1 - C3

• Spinous processes of all vertebra except C2
• (fibers insert 2-4 segments superior to origin)

Posterior rami of spinal nerves (segmental)

• Extension
• Stabilizes vertebrae during local movements of vertebral column

• Transverse processes of vertebrae
• (developed best in thoracic region)

• Junction of lamina and transverse process of vertebra immediately superior to origin
• (1 segment = brevis)
• (2 segments = longus)

Posterior rami of spinal nerves (segmental)

Rotate the spine!

Interspinales / Intertransversarii / Levatores Costarum (Medial to Lateral)

Minor role in spinal stability

Posterior Rami EXCEPT the lateral parts of intertransversarii m. (anterior rami)

• Unilaterally
• Lateral flexion to ipsilateral side
• Control bending to contralateral side

• Bilaterally
• Trunk extension
• Stabilize during flexion

• Unilaterally
• Rotation

• Bilaterally
• Stabilization

• Unilaterally
• Rotation

• Bilaterally
• Head flexion / extension