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