Where is the anterior thoracolumbar fascia located?

• A. Lateral to pectoralis major
• B. Attached to iliac crest, anterior to lumbar transverse processes and 12th rib
• C. Surrounds kidneys
• D. Deep to the diaphragm

Answer: (B)

The anterior layer of the thoracolumbar fascia sits in the posterior abdominal wall as a strong sheet that encases the psoas major and quadratus lumborum. It attaches laterally to the iliac crest and extends medially to the transverse processes of the lumbar vertebrae and to the inner surface of the 12th rib, lying in front of those lumbar muscles. This placement—anchored to the iliac crest and positioned anterior to the lumbar transverse processes and the 12th rib—matches the description of the anterior thoracolumbar fascia, making it the best choice. The other options describe structures or relationships that don’t apply to this fascia: it does not envelop the kidneys (renal fascia does), it isn’t located deep to the diaphragm, and it isn’t merely lateral to the pectoralis major.