Origin/Proximal Attachment Middle lip of the iliac crest; Linea alba; lower borders of the lateral 1/3 of the inguinal ligament; thoracolumbar fascia Insertion/Distal Attachment Unilateral: lower 3 or 4 ribs Action/Relevance Intercostal nerves (7th-12th) Rotates trunk to same side of contractionLaterally flexes trunk to same side of contraction Bilateral: Flexes the trunk4. Compresses the abdomen Innervation Iliohypogastric nerves (T12, L1) Ilioinguinal nerves (T12, L1) | 
