QS Study

The diaphragm is a dome-shaped muscle forming the partition between the thoracic and abdominal cavities. It is the primary muscle used in respiration, which is the process of breathing. This dome-shaped muscle is located just below the lungs and heart. It is the main muscle of inspiration and holds the most vital value for the overall procedure of exchange of gases.

Development of diaphragm

(i) Muscle and central tendon – From septum transyersum. It is a thick mass of cranial mesenchyme that gives rise to parts of the thoracic diaphragm and the anterior mesentery of the foregut in the adult.

(ii) Peripheral areas of the diaphragmatic pleura and peritoneum that cover its lower surfaces; from pleuroperitoneal membranes. The parietal pleura is innervated by the intercostal nerves and the phrenic nerve

(iii) Crura: From the dorsal mesentery of oesophagus. Two pillars connecting the spinal column and diaphragm. There are right crus and a left crus, which together form a tether for muscular contraction.

Developmental anomalies

Diaphragmatic hernia –

(i) Retrosternal hernia.

(ii) Posterolateral hernia.

(iii) Posterior hernia.

(iv) Central hernia.