CMD 272 Lecture Notes - Lecture 7: Rectus Abdominis Muscle, Transverse Abdominal Muscle, Subcostal Nerve
Document Summary
Cmd 272 - lecture 7 - muscles of expiration. Expiration is an active process in speech and heavier breathing. Muscles act on the lungs squeeze the air out of them. Involves reducing the size of the thoracic cavity in 2 dimensions; vertical and front-to-back. Muscles are going to be pulling the rib cage down. Origin superior margin of each rib, except the 1st. Anterior; are not present on the posterior part of the rib cage near the vertebral. Insertion up and medially into the inferior surface of the rib above column. Run on an opposite angle to the external intercostals. Gives support and strength to the rib cage. Anterior; found on the inner surface of the rib cage. Contraction resists elevation of the rib cage. Insertion fibers course to the inner chondral surface of ribs 2-6. Found on the inner posterior wall of the thorax. Origin spinous processes of t11-t12, l1-l3. Insertion lower margin of lower 5 ribs.