• Describe the development and structure of the diaphragm

the diaphragm is formed in the area of the thoracic inlet within neck in initial embryonic development. when the lungs begin to form they push down the diaphragm to eventually become the superior border of the abdomen which seperates the abdomen from the thorax. the reason that the phrenic nerve (C3,4,5) innervates the diaphragm is because of the fact that it was originally developed in the neck region where the phrenic nerve originates and so when the lungs push the diaphragm down it pulls vessels and nerves with it.

the diaphragm has 4 sources of origin

septum transversum

2 pleural peritoneal folds/membranes

ingrowth from the body

the oesophagus

anteriorly the muscle fibres arise from

• xiphoid process
• ribs 11 & 12

posteriorly

• lateral and medial arcuate ligaments

ALL of the listed above fibres converge onto the central tendon of the diaphragm

• Describe the openings in the diaphragm and the structures that pass through them