| A | B |
|---|
| Origin of the Pectoralis major | Medial clavicle, sternm and the cartilage of ribs 1 though 6 |
| Insertion of the Pectoralis major | crest of the greater tubercle of the humerus |
| Major action of the Pectoralis major | Horizontally dduct the humerus at the glenohumeral joint |
| Origin of the Pectoralis minor | Anterior surface of ribs 3,4, and 5 |
| Insertion of the Pectoralis minor | Coracoid process |
| Major action of the Pectoralis minor | Tilt the scapula anteriorly |
| Origin of the Serratus anterior | Anterior surface of upper 8 or 9 ribs |
| Insertion of the Serratus anterior | Anterior surface of the medial border of the scapula |
| Major action of the Serratus anterior | Abduct the scapula at the scapulothoracic joint |
| Origin of the diaphragm | inner surface of lower 6 ribs, upper two or 3 lumbar vertebra and the xiphoid process |
| Insertion of the diaphragm | Central tendon |
| Action of the diaphragm | Increase the volume of the thoracic cavity during inhalation |
| Origin of the intercostals | Inferior border of the rib (above) |
| Insertion of the intercostals | Superior border of the rib (below) |
| Action of the internal intercostals | draw ribs inferiorly and assist with exhalation |
| Action of the external intercostals | lift ribs and assist with inhalation |
| Origin of the Rectus abdominis | Pubic crest and symphysis |
| Insertion of the Rectus abdominis | xiphoid process and the anterior surface and cartilage of ribs 5,6,7 (the middle ribs) |
| Action of the Rectus abdominis | Flex the vertebral column |
| Origin of the External obliques | lower 8 ribs |
| Insertion of the External obliques | Anterior iliac crest and abdominal aponeurosis |
| Action of the External oblique (unilateral) | laterally flex vertebral column and rotate to the opposite side |
| Origin of the Internal obliques | anterior iliac crest, inguinal ligament and abdominal aponeurosis |
| Insertion of the Internal obliques | Internal surface of lower ribs |
| Action of the Internal obliques (unilateral) | laterally flex and rotate vertebral to the same side |
| Action of the obliques (bilaterally) | flex the vertebral column |
| Action of the Transverse abdominis | compress the abdominal contents |
