Muscle | Origin | Insertion | Action | Inervation |
External Abdominal Oblique | Ext. surface lower 8 ribs | Aponeurosis to linea alba, xiphoid process, ant. iliac crest and pubic tubercle | (blank) | Lower 6 thoracic and upper 2 lumbar |
Internal Abdominal Oblique | Lateral 2/3 on inguinal ligament, ant. 2/3 of iliac crest, lumbar aponeurosis | Lower border of ribs 10-12 with aponeurosis to linea alba, pectineal line of pubis | (blank) | Lower 6 thoracic and uper 2 lumbar, iliohypogastric and ilioinguinal |
Transverse Abdominus | Lat. 1/3 of inguinal lig, inner lip of iliac crest, thoracolumbar fascia, cratilages of ribs 7-12 | Aponeurosis to linea alba, pectineal line of pubis | (blank) | Intercostal nerves 7-12, iliohypogastric and ilioinguinal |
Rectus Abdominus | Pubic tubercle and superior pubic lig. | Cartilages of ribs 5-7, xiphoid process | Flex vertebral column, posterior tiping of coxals | Intercostal nerves 7-12, iliohypogastric and ilioinguinal |
Quadratus Lumborum | Iliolumbar ligs, posterior iliac crest | Lower border of rib 12, tips of transverse processi of first 4 lumbar vertebrae | Lat. flexion of vertebral col., depress 12th rib, assist forced expiration | Subcostal nerves and lumbar s.n. 1-3 |
Psoas Major | Transverse processi, sides of bodies and intervertebral discs of T12-L5 | Lesser trochanter of femur | Flexion, lat. rotation of femur. Flex vertebral column when thigh fixed (sit-up) | Lumbar s.n. 2 and 3 |
Iliacus | Upper iliac fossa, iliac crest, ant. sacroiliac lig., and base of sacrum | Lesser trochanter of femur | Flex femur | Femoral nerve (L2-L4 s.n.) |
Pyramidalis | Pubis and superior pubis lig. | Linea alba | Tenses linea alba | Subcostal nerve, s.n. T12 |
Psoas Minor | Vertebral margins of T12 and L1 | Pectineal line of pubis | Elevates pelvis, minor | Lumbar s.n. 1 |
External Intercostal | Inf. border of adjacent sup. rib | Superior border of adjacent inf. rib | Elevate/fixate intercostal space | Intercostal nerves |
Internal Intercostal | Superior border of adjacent inf. rib | Inferior border of adjacent sup. rib | Depress/fixate intercostal space | Intercostal nerves |
Diaphragm | Xiphoid process, costal cartilages of ribs 7-12, L1-L3 | Central tendon of the diaphragm | Respiration | Phrenic nerve |
Transverse Thoracis | Internal surfaces of body of sternum, xiphoid process, costal cartilages of ribs 4-6 | Lower border and internal surface of ribs 2-6 | Depress ribs 2-6 | Upper 6 intercostal nerves |
Subcostals | Internal surface of rib near angle | Superior border of rib 1-3 ribs below | Compression | Intercostal nerves |
Serratus Posterior Superior | Ligamentum nuchae, last cervical spine and thoracic spines 1-3 | Superior border of ribs 2-5 just past angle | Elevate/fixate ribs 2-5 | ventral rami of thoracic s.n. 1-3 |
Serratus Posterior Inferior | Last 2 thoracic and first 2 lumbar spines | Inferior border of lower ribs 9-12 | Depress/fixate ribs 9-12 | ventral rami of last four thoracic s.n. 9-12 |
Levatores Costarum | Tips of transverse processi of C7-T11 | External surface of rib below | Elevate T1-12 | Ventral rami of thoracic spinal nerves in the area |
Scalenus Anterior | Ant. tubercles of trans. processi of C3-C6 | Superior surface of 1st rib | Elevate 1st rib, lat flexion of C3-C6, rotate C3-C6 | Ventral rami, cervical s.n. 5-8 |
Scalenus Medius | Posterior tubercles C2-C7 | Superior surface of 1st rib | Elevate 1st rib, lat flexion of C2-C7, rotate C2-C7 | ventral rami, cervical s.n. 3-4 |
Scalenus Posterior | Posterior tubercles of transverse processi C4-C6 | Superior surface of 2nd rib | Elevate 2nd rib, lat flexion C4-C6, rotate C4-C6 | Ventral rami, cervical s.n. 3-8 |