The medial arcuate ligament (also medial lumbocostal arch and internal arcuate ligament) is a tendinous fascia that arches over the

psoas major The psoas major ( or ; from ) is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the iliopsoas. In other animals, this muscle is e ...

muscle as it passes posterior the

diaphragm Diaphragm may refer to: Anatomy * Thoracic diaphragm, a thin sheet of muscle between the thorax and the abdomen * Pelvic diaphragm or pelvic floor, a pelvic structure * Urogenital diaphragm or triangular ligament, a pelvic structure Other * Diap ...

. The purpose of the medial arcuate ligament is to attach the diaphragm to the spine (lumbar vertebra L1 - L2)

Structure

The medial arcuate ligament is an arch in the fascia covering the upper part of the

. It is attached to the side of the body of the first or second

lumbar vertebra The lumbar vertebrae are located between the thoracic vertebrae and pelvis. They form the lower part of the back in humans, and the tail end of the back in quadrupeds. In humans, there are five lumbar vertebrae. The term is used to describe the ...

, laterally, it is fixed to the front of the transverse process of the first and, sometimes also, to that of the second lumbar vertebra. It lies between the

lateral arcuate ligament The lateral arcuate ligament (also lateral lumbocostal arch and external arcuate ligament) is a ligament under the diaphragm that arches across the upper part of the quadratus lumborum muscle. It is traversed by the subcostal nerve, artery and vei ...

and the midline

median arcuate ligament The median arcuate ligament is a ligament under the diaphragm that connects the right and left crura of diaphragm. Structure The median arcuate ligament is formed by the right and left crura of the diaphragm. The crura connect to form an ar ...

. The sympathetic chain enters the abdomen by passing deep into this ligament of the diaphragm. This is in contrast to the parasympathetic

vagus nerve The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fibe ...

which passes through the

esophageal hiatus In human anatomy, the esophageal hiatus is an opening in the diaphragm through which the esophagus and the vagus nerve pass. Structure The esophageal hiatus is an oval opening in (sources differ) the right crus of the diaphragm/left crus of the ...

References

External links

* * () Ligaments of the torso Thoracic diaphragm {{ligament-stub