Back Muscles

Question 1

Splenius Capitis

Answer 1

Action:

• Unilaterally: Rotate the head and neck to the same side, laterally flex the head and neck.
• Bilaterally: Extend the head and neck.

O: Ligamentum nuchae, spinous processes of C-7 to T-3

I: Mastoid process and lateral portion of superior nuchal line.

N: Cervical.

Question 2

Splenius Cervicis

Answer 2

Action:

Unilaterally: Rotate the head and neck to the same side, laterally flex the head and neck. Bilaterally: Extend the head and neck.

O: Spinous process of T-3 to T-6

I: Transverse processes of C1-C3

N: Cervical

Question 3

Suboccipitals

Answer 3

• Rectus capitis posterior major (N: Suboccipital)
• Rectus capitis posterior minor (N: Suboccipital)
• Oblique capitis superior (N: Suboccipital)
• Oblique capitis inferior (N: Suboccipital)

General action: rotate and tilt head into extension

Question 4

Erector Spinae Group

Answer 4

(1) Spinalis:

O: spinous processes of upper lumbar and lower thoracic vertebrae & C7

I: spinous processes of upper thoracic, cervicals

(2) Longissimus:

O: (thoracic) common tendon; (cervical and capitis) transverse processes of T1-T5

I: (thoracic) lower 9 ribs and transverse process of T-S vertebrae,(cervical) transverse processes of C-S vertebrae, (capitis) mastoid process of temporal bone

(3) Iliocostalis:

O: (lumborum) common tendon; (thoracic & cervical) posterior surface ribs 1-12

I: (lumbarum) transverse processes of L1-L3 & posterior ribs 6-12; (thoracic) posterior ribs 1-6; (cervical) transverse processes of lower cervicals

Action:

• Unilaterally: Laterally flex vertebral column to the same side
• Bilaterally: Extend the vertebral column

N: Spinal

Question 5

Transversospinalis Group

Answer 5

Multifidi and Rotatores

Action:

• Unilaterally: Rotate the vertebral column to the opposite side.
• Bilaterally: Extend the vertebral column

O:

• Multifidi: Sacrum and transverse processes of lumbar through cervical vertebrae
• Rotatores: Transverse processes of lumbar through cervical vertebrae.

I: Spinous processes of lumbar vertebrae through second cervical vertebrae (multifidi span two to four vertebrae)(rotatores span one to two vertebrae)

N: Spinal

Question 6

Semispinalis Capitis

Answer 6

A: Extend the vertebral column and head

O: Transverse process of C4-T5

I: Between the superior and inferior nuchal line of occiput

N: Cervical

Question 7

Quadratus Lumborum

Answer 7

Action:

• Unilaterally: Laterally tilt the pelvis, laterally flex the vertebral column to the same side, assist to extend the vertebral column
• Bilaterally: Fix the last rib during inhalation and forced exhalation

O: Posterior iliac crest

I: Last rib and transverse processes of first through fourth lumbar vertebrae

N: Lumbar plexus T12, L1, L2, L3