8.Diaphragm

• Diaphragm


  • Arises from the Xiphoid process, lower six costal cartilages, vertebrae L1 to L3 for the right crus and vertebrae L1 to L2 for the Left crus
  • Motor from the Phrenic nerve
  • Sensory: Central part – Phrenic nerve, Peripheral – Intercostal nerves
• Phrenic nerve


  • Only motor nerve supply to the Diaphragm
  • Arises from C3, C4 and C5
• Structures transmitted by the Aortic opening

  • Azygous vein
  • Aorta
  • Thoracic duct
• CAVAL HIATUS


  Lies in the central tendon at the level of T8
• ESOPHAGEAL HIATUS


  Lies in the muscular part at the level of T 10
• AORTIC HIATUS


  Lies between the two crura at the level of T 12
• CAVAL – T8


  • IVC
  • Right Phrenic Nerve
• ESOPHAGEAL- T 10


  • Esophagus
  • Vagus Nerve
• AORTIC – T 12

  • Aorta
  • Thoracic Duct
  • Azygous Vein
• Right lymphatic duct


  Drains the Right side of the body above the diaphragm
• Lymphatic vessels


  • Thoracic duct
  • Right Lymphatic duct
• Right Lymphatic duct drains

  • Right side of head & neck
  • Right side of thorax
  • Right upper limb
• Thoracic duct


  Empties into the Left Brachiocephalic vein
• Thoracic duct


  1. Begins in the abdomen at the Cisterna chyli

  2. Drains the lower limbs, pelvis, abdomen, left thorax, left upper limb and left side of the head and neck

  3. Passes the aortic opening of the diaphragm and ASCENDS through the POSTERIOR MEDIASTINUM between the aorta and the azygous vein

  4. Arches laterally over the apex of the left pleura and between the left carotid sheath in front and vertebral artery behind, runs behind the left internal jugular vein

  5. EMPTIES into the JUNCTION of the Left Internal Jugular and Subclavian veins
• Diaphragm Openings

  • Caval hiatus
  • Esophageal hiatus
  • Aortic hiatus