Trunk and Back Muscles (Trail Guide)

Question 1

Intercostals

Answer 1

A: (External Intercostals) - Draw the ribs superiorly (increasing the space of the thoracic cavity) to assist with inhalation
(Internal Intercostals) - Draw the ribs inferiorly (decreasing the space of the thoracic cavity to assist with exhalation
(Innermost intercostals) - Draws ribs inferiorly

O: Inferior border of the rib above

I: Superior border of the rib below

N: Thoracic spinal nerves; Intercostal nerves (powerpoint)

Question 2

Splenius Capitus and Cervicis

Answer 2

A: (Unilaterally)
Rotate head/neck to the same side
Laterally flex the head and neck to the same side
(Bilaterally)
Extend the head and neck

O: Capitis - Inferior 1/2 of ligamentum nuchae and spinous processes of C7-T4
Cervicis - Spinous processes of T3-T6

I: Capitis - Mastoid process and lateral portion of superior nuchal line
Cervicis - Transverse processes of C1-C3

N: Cervical

Question 3

Iliocostalis

Answer 3

A: (Unilaterally) - Laterally flex vertebral column to the same side
(Bilaterally) - Extend the vertebral column

O: Common tendon (Lumborum); Posterior surface of ribs 1-12 (thoracis and cervicis)

I: Transverse processes of lumbar vertebrae 1-3 and posterior surface of ribs 6-12 (Lumborum);
Posterior surface of ribs 1-6 (thoracis);
Transverse processes of lower cervicals (cervicis)

N: Spinal nerves

Question 4

Longissimus

Answer 4

A: (Unilaterally) - Laterally flex vertebral column to the same side
(Bilaterally) - Extend the vertebral column

O: Common tendon (thoracis); Transverse processes of upper five thoracic vertebrae (cervicis and capitis)

I: Lower nine ribs and transverse processes of thoracic vertebrae (thoracis);
Transverse processes of cervical vertebrae (cervicis);
Mastoid process of temporal bone (capitis)

N: Spinal nerves

Question 5

Spinalis

Answer 5

A: (Unilaterally) - Laterally flex vertebral column to the same side
(Bilaterally) - Extend the vertebral column

O: Spinous processes of upper lumbar and lower thoracic vertebrae (thoracis);
Ligamentum nuchae, spinous process of C7 (cervicis)

I: Spinous processes of upper thoracic (thoracis);
Spinous processes of cervicals, except C1 (cervicis)

N: Spinal

Question 6

Multifidus

Answer 6

A: (Unilaterally) - Rotate the vertebral column to the opposite side
(Bilaterally) - Extend the vertebral column

O: Sacrum and transverse processes of lumbar through cervical vertebrae

I: 2-4 vertebrae up of spinous processes to 2nd cervical vertebrae

N: Spinal

Question 7

Rotatores

Answer 7

A: (Unilaterally) - Rotate the vertebral column to the opposite side
(Bilaterally) - Extend the vertebral column

O: Transverse processes of lumbar through cervical vertebrae

I: 1-2 vertebrae up of spinous processes, lumbar through second cervical vertebrae

N: Spinal