Trunk O/I/Inn/A

• diaphragm


  O: Costal part - Inferior border of the ribs (7-12) Lumbar part - Vertebral bodies L1-L3, ALL, arcuate ligament Sternal part - Posterior surface of xiphoid process; I: central tendon; Inn: phrenic nerve (C3-C5); BS: lower intercostal arteries, subcostal artery, musculophrenic artery, pericardiophrenic artery and inferior phrenic arteries; A: Inspiration, increase volume of thoracic cavity and increase intraabdominal pressure
• transverse thoracis


  O: posterior surface of sternum and xiphoid process; I: posterior surface (costal cartilages) of rubs 2-6, anterior thoracic wall; Inn: intercostal nerves 2-6; BS: intercostal arteries; A: weakly depress ribs
• subcostal muscle


  O: internal surface of lower ribs; I: superior border of inferior ribs (skips 2 & 3), posterior thoracic wall; Inn: intercostal nerves 2-6; BS: intercostal arteries; A: depress ribs
• Levatores Costarum


  O: transverse processes C7-T11; I: costal angle of next lower rib or two ribs below, posterior thoracic wall; Inn: posterior rami of C8-T11; BS: intercostal arteries; A: elevate ribs
• External Intercostals


  O: inferior border of rib; I: superior border of inferior rib, fibers run anterior and inferior from origin to insertion, ends at costochondral junction and continues with the external intercostal membrane; Inn: intercostal nerves (T1-T11); BS: intercostal arteries; A: elevate ribs during inspiration
• Internal intercostals


  O: superior border of inferior rib; I: inferior border of superior rib (deep to external intercostals), fibers run ant and sup at a 90 degree angle to ext intercostals, from the sternum to the costal angle; Inn: intercostal nerves (T1-T11); BS: intercostal arteries; A: depress ribs during expiration
• innermost intercostals


  O: superior border of inferior rib; I: inferior border of superior rib (deep to internal intercostals), fibers run ant and sub at a similar angle to int intercostals, occupies lateral 1/3 of the thoracic wall; Inn: intercostal nerves (T1-T11); BS: intercostal arteries; A: depress ribs during forced expiration
• external abdominal oblique


  O: external surface of ribs 5-12; I: linea alba, pubic tubercle and anterior half of iliac crest; Inn: thoracoabdominal nerves (T7-T11), subcostal nerve (T12); BS: superior epigastric arteries, musculophrenic arteries, subcostal artery, posterior intercostal arteries, lumbar arteries, and inferior epigastric arteries; A: trunk flexion and lateral flexion to ipsilateral side/ rotation to contralateral side, forced expiration and increase pressure in abdominal cavity
• internal abdominal muscle


  O: thoracolumbar fascia, anterior half of iliac crest (inguinal ligament), ASIS and iliopsoas fascia; I: ribs 10-12, linea alba; Inn: thoracoabdominal nerves (T7-T11), subcostal nerve (T12); BS: superior epigastric arteries, musculophrenic arteries, subcostal artery, posterior intercostal arteries, lumbar arteries, inferior epigastric arteries; A: trunk flexion and lateral flexion to ipsilateral side/rotation to ipsilateral side, forced expiration and increase pressure in abdominal cavity
• rectus abdominis


  O: pubic crest, pubic tubercle and pubic symphysis; I: costal cartilages 5-7, xiphoid process of sternum; Inn: intercostal nerves (T5, T6), thoracoabdominal nerves (T7-T11), subcostal nerve (T12); BS: superior epigastric arteries and inferior epigastric arteries, musculophrenic arteries, anterior intercostal arteries; A: trunk flexion, increase pressure in abdominal cavity
• transversus abdominis


  O: thoracolumbar fascia, costal cartilages 7-12, iliac crest, ASIS, and iliopsoas fascia; I: pubic crest and linea alba, Inn: intercostal nerves (T5-T6), thoracoabdominal nerves (T7-T11), subcostal nerve (T12); BS: superior epigastric arteries, musculophrenic arteries, subcostal artery, posterior intercostal arteries, lumbar arteries, inferior epigastric arteries; A: increase pressure in abdominal cavity, rotation to ipsilateral side