The Back (Intrinsic muscle Actions and Innervations)

Question 1

Erector spinae group muscles (A & Inn)

Answer 1

A: bilaterally= extend vertebral column & head
Unilaterally: laterally flex vertebral column

Inn: dorsal rami of spinal nerves

Question 2

Semispinalis (A & Inn)

Answer 2

A: extend head, thoracic, & cervical regions; rotates them contralaterally

Inn: dorsal rami

Question 3

Multifidus (A & Inn)

Answer 3

A: stabilizes vertebrae during localized movements of vertebral column

Inn: dorsal root rami

Question 4

Rotatores (A & Inn)

Answer 4

A: extend head, thoracic & cervical regions; rotates them contralaterally

Inn: dorsal rami

Question 5

Of the three segmental muscles (interspinales, intertransversari, levator costarum) which has some innervation from the ventral rami?

Answer 5

intertransversari

Question 6

Splenius

- Capitis & cervicis (A & Inn)

Answer 6

A: bilaterally= extend head and neck
Unilaterally= laterally flex neck and rotate head to side of contracting muscle

Inn: dorsal rami of spinal nerves