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 costs for installing and staining a concrete floor are very reasonable, at about $3 to $15 dollars per square foot, depending on what type of stain and sealant are used, and whether an artisan is used to create patterns or decorative effects on the floor.he costs for installing and staining a concrete floor are very reasonable, at about $3 to $15 dollars per square foot, depending on what type of stain and sealant are used, and whether an artisan is used to create patterns or decorative effects on the floor.