I.A.2 Back: Muscles (Deep, Intermediate, Superficial): Page 1 of 3

Objectives:

1.2.1 Identify the deep back muscles in each region (Cervical, Thoracic, Lumbar, and Sacral) indicate their vertebral location, innervation and the function of each muscle group.

1.2.2 Identify the muscles of the superficial and intermediate layers of the back. Indicate the innervation and the function of each muscle layer.

Assigned Readings:

Moore's COA pages: 116-127. See blue boxes on pages 127-128 for clinical correlations. See the yellow box on page 28 for "The Bottom Line."

Step 1: Begin with the back vertebral column.

Now let's add the members of the deep back muscles.

When working in equilibrium, they stiffen the spine so we can stand erect.
When working unilaterally, they cause the spine to rotate in the direction of contraction.
When all are contracting, they cause the spine to hyperextend posteriorly.

	Step 2: Add the rotatores group which helps with rotation of the spine.
	Step 3: Add the intertransversarii group.
	Step 4: Add the semispinalis group which has a subgroup (semispinalis capitus) which, when contracted, bilaterally extends the head posteriorly. When contracting unilaterally, assists in turning the head.
	Step 5: Add the spinalis group.
	Step 6: Add the longissimus group.
	Step 7: Add the iliocostalis group.
	Step 8: Add the splenius group.