Quadratus Lumborum
Abdomen & Core
A common culprit for lower back pain — often mistaken for a 'pulled back.'
Function
Laterally flexes trunk, fixes 12th rib during deep breathing
Origin
Iliac crest and iliolumbar ligament
Insertion
12th rib and transverse processes of L1-L4
Innervation
Subcostal nerve (T12) and ventral rami L1-L4