Origin of diaphragm1- Sternal origin: Back of xiphoid
process of sternum.2- Costal origin: Inner aspect of lower
6 ribs.3- Vertebral origin: a. Two crura:• Right crus arises from
the ventral aspect of the upper three lumbar vertebrae.
• Left crus arises from the upper two lumbar vertebrae.
Origin of diaphragmb. Arcuate ligaments:* Median arcuate ligament: A median tendinous arch
connecting the right and left crura.
* Medial arcuate ligament: On each side, connecting
each crus with the tip of transverse process of L1.
* Lateral arcuate ligament: On each side, connecting
the tip of transverse process of L1 with the last rib.
Insertion of diaphragmInto the central
tendon of diaphragm which is formed of three lobes:
1- right lobe.
2- left lobe.
3- median lobe.
* The central tendon is depressed and the lateral parts are elevated forming the right and left copula.
Nerve supply and actionNerve supply:1- Phrenic nerve: motor, sensory.2- Lower intercostal nerves: sensory.Action:1- Muscle of respiration.2- Increase the intra abdominal pressure in
forced actions.3- right crus acts as a sphincter to the
lower end of oesophagus.
Major openings in the diaphragm
Major openings in the diaphragm1- IVC opening:a.Site: In the
central tendon of diaphragm between right and median lobe.
b.Level: T8c.Structures
passing through: 1)IVC.2)Right phrenic
nerve.3)Lymphatics.
Major openings in the diaphragm2- Aortic
opening:a.Site: Posterior to
median arcuate ligament.
b.Level: T12c.Structures
passing through: 1)Aorta.2)Azygos vein.3)Thoracic duct.
Major openings in the diaphragm3- Oesophageal
opening:a.Site:Right crus.b.Level: T10c.Structures passing
through: 1)Oesophagus.2)Vagi.3)Anastomotic
branches between left gastric and aortic oesophageal arteries.
Other structures passing through the diaphragm
1-Splanchnic nerves which pierce the crura.
2-Inferior hemiazygos vein which pierce the left crus.
3-Psoas major M.4-Sympathetic trunk.*3,4 pass deep to the
medial arcuate ligament.
5-Quadratus lumborum.
6- Subcostal N, Vs.*5,6 Pass deep to the
lateral arcuate ligament.
Other structures passing through the diaphragm
7-Lower five intercostal Ns, Vs between the slips of the costal origin of diaphragm.
8-Superior epigastric vessels between sternal and costal origin.
9-Musculo phrenic vessels between the 7th and 8th costal slips.
Prof.: Dr. Wafaa Abdel-Rahman