There are three principal layers; 1  External intercostal muscles aid in quiet and forced inhalation. They originate on ribs 1-11 and have their insertion on ribs 2-12. 2  Internal intercostal muscles aid in forced expiration (quiet expiration is a passive process).
Costs. A professional concrete contractor will typically charge $2-$4 per square foot for a simple stain application, including the sealer. A stain application with patterning and sawed lines will typically cost between $4 and $10 per square foot.
1 For those that want to get acid stained concrete work done outside, a simple stained concrete job can vary anywhere from $2 to $5 per square foot. 2  Interior jobs are slightly more since more work will be required in order to lay concrete in the home.