Editing Diaphragm (section)

== '''Structure''' ==

* Arises from the posterior     surface of the xiphoid process, the inner sides of the lowest six ribs,     from the fascial arches (medial and lateral arcuate ligaments) and from     the upper lumbar vertebrae via the crura. The muscle fibres pass centrally     to insert on the central tendon.
* Crura of the diaphragm -     musculotendinous structures, embryologically distinct from the remainder     of the diaphragm
** Arise from the anterior      surfaces and discs of L1-L3, as well as the anterior longitudinal      ligament of the spine
** The right crus tends to      reach slightly lower in its origin from the first three lumbar vertebrae
** Left crus only from L1 and      L2
** Tendinous fibres are more      posteriorly - these parts hold sutures best, so hiatus hernia repair      works best posteriorly
** Quite variable arrangement      of fibres at the crura
* Central tendon
** Interlaced fibres
** Inseparable from the fibrous      pericardium
* Posterior ligaments
** Median arcuate ligament -      tendinous fibres from the medial edge of each crus unite with each other      in front of the aorta at T12
** Medial arcuate ligament
*** Thickening of the psoas       fascia
*** Extends from the lower part       of the body of the L1/2 vertebrae to a ridge on the anterior surface of       the transverse process of L1 (at the lateral border of psoas)
*** Sympathetic trunk passes       behind
** Lateral arcuate ligament
*** Thickening of the anterior       layer of lumbar fascia
*** From the transverse process       of L1 to the 12th rib (at the lateral border of quadratus lumborum)
*** Subcostal nerve and vessels       pass behind