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.
The cost to resurface a concrete slab can vary quite a bit. Basic grey cement color over a fairly good condition of concrete could be as low as 2.25 per square foot whereas an intricate pattern, multicolor and borders can run you in the price range of $4 to $8 per square foot.cid stain: Sometimes referred to as acid etch, acid wash or acid washed concrete, patina stain etc. This system is used to add a permanent color to an existing or freshly poured cement topping or concrete slab. Prices can range from $2 per square foot to $7 for a basic application.