Lies edge to edge with Psoas Major medially and Transverse Abdominis laterally
- Lies in anterior compartment of Lumbar Fascia
- Represents the innermost of the 3 muscular layers of body wall, i.e. in series with Diaphragm and Transversus Thoracis muscle group
- Origins:
- Transverse process of L5
- Iliolumbar Ligament
- Iliac Crest
- Insertion:
- Transverse processes of L1 – L4 (Lateral to Psoas Major)
- Inferior border of medial half of 12th Rib
- Nerve Supply:
- T12 and L1-L3/L4 Lumbar Nerves
- Action:
- Prevent the diaphragm from elevating 12th rib during inspiration
- Lateral flexion of Lumbar Spine
