Iliocostalis Lumborum O, I, A
Origin: The iliolumbar fascia, the posterior medial lip of the iliac crest, the lateral crest of the sacrum, and the spinous processes of T11 to L5
Insertion: Inferior borders of the angles of the lower six or seven ribs
Actions: Extension and lateral flexion of the thoracic spine, extension and lateral flexion of the lumbar spine
Innervation: Dorsal primary rami of T11 to L5
Blood Supply: Intercostal and lumbar arteries
Primary Actions of the Iliocostalis Lumborum
1. Extension of the thoracic spine when acting bilaterally
Agonists:
- Iliocostalis cervicis
- Iliocostalis thoracis
- Longissimus cervicis
- Longissimus thoracis
- Spinalis thoracis
- Semispinalis cervicis
- Semispinalis thoracis
Antagonists:
- Rectus Abdominis
2. Lateral flexion of the thoracic spine when acting unilaterally
Agonists:
- Iliocostalis cervicis
- Iliocostalis thoracis
- Longissimus cervicis
- Longissimus thoracis
- External Oblique
- Internal Oblique
Antagonists: Same muscles on contralateral side
- Iliocostalis cervicis
- Iliocostalis thoracis
- Longissimus cervicis
- Longissimus thoracis
- External Oblique
- Internal Oblique
3. Extension of the lumbar spine when acting bilaterally
Agonists:
- Longissimus thoracis
- Spinalis thoracis
Antagonists:
- Rectus Abdominis
4. Lateral flexion of the lumbar spine when acting unilaterally
Agonists:
- Longissimus thoracis
- Psoas major
- Quadratus lumborum
- External oblique
- Internal oblique
Antagonists: Same muscles on contralateral side
- Longissimus thoracis
- Psoas major
- Quadratus lumborum
- External oblique
- Internal oblique
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Information about cause and effect of Iliocostalis Lumborum pain: Iliocostalis Lumborum Muscle: Low Back and Buttock Pain
An excellent book for those beginning the study of anatomy. Coloring helps memory retention.
For intermediary anatomy students learning skeletal and muscle structure.
For beginning and intermediary anatomy . Muscle overlays on the human body. Excellent visuals!